diff --git a/src/main/java/com/googlesource/gerrit/plugins/importer/ImportProject.java b/src/main/java/com/googlesource/gerrit/plugins/importer/ImportProject.java
index 74b8eb0..6d1f3bb 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/importer/ImportProject.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/importer/ImportProject.java
@@ -19,7 +19,6 @@
 
 import com.google.common.base.Strings;
 import com.google.gerrit.common.errors.NoSuchAccountException;
-import com.google.gerrit.extensions.annotations.PluginData;
 import com.google.gerrit.extensions.annotations.RequiresCapability;
 import com.google.gerrit.extensions.restapi.BadRequestException;
 import com.google.gerrit.extensions.restapi.ResourceConflictException;
@@ -92,7 +91,7 @@
   private final Provider<CurrentUser> currentUser;
   private final ImportJson importJson;
   private final ImportLog importLog;
-  private final File lockRoot;
+  private final ProjectsCollection projects;
 
   private final Project.NameKey targetProject;
   private Project.NameKey srcProject;
@@ -112,7 +111,7 @@
       Provider<CurrentUser> currentUser,
       ImportJson importJson,
       ImportLog importLog,
-      @PluginData File data,
+      ProjectsCollection projects,
       @Assisted Project.NameKey targetProject) {
     this.projectCache = projectCache;
     this.openRepoStep = openRepoStep;
@@ -123,7 +122,8 @@
     this.currentUser = currentUser;
     this.importJson = importJson;
     this.importLog = importLog;
-    this.lockRoot = data;
+    this.projects = projects;
+
     this.targetProject = targetProject;
   }
 
@@ -246,7 +246,7 @@
   }
 
   private LockFile lockForImport() throws ResourceConflictException {
-    File importStatus = new File(lockRoot, targetProject.get());
+    File importStatus = projects.FS_LAYOUT.getImportStatusFile(targetProject.get());
     LockFile lockFile = new LockFile(importStatus, FS.DETECTED);
     try {
       if (lockFile.lock()) {
diff --git a/src/main/java/com/googlesource/gerrit/plugins/importer/ProjectsCollection.java b/src/main/java/com/googlesource/gerrit/plugins/importer/ProjectsCollection.java
index 80594ab..81dfc31 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/importer/ProjectsCollection.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/importer/ProjectsCollection.java
@@ -37,6 +37,14 @@
     ChildCollection<ConfigResource, ImportProjectResource>,
     AcceptsCreate<ConfigResource> {
 
+  class FileSystemLayout {
+    File getImportStatusFile(String id) {
+      return new File(lockRoot, id);
+    }
+  }
+
+  public final FileSystemLayout FS_LAYOUT = new FileSystemLayout();
+
   private final DynamicMap<RestView<ImportProjectResource>> views;
   private final ImportProject.Factory importProjectFactory;
   private final Provider<ListImportedProjects> list;
@@ -67,7 +75,7 @@
 
   public ImportProjectResource parse(String id)
       throws ResourceNotFoundException {
-    File f = new File(lockRoot, id);
+    File f = FS_LAYOUT.getImportStatusFile(id);
     if (!f.exists()) {
       throw new ResourceNotFoundException(id);
     }
diff --git a/src/main/resources/Documentation/about.md b/src/main/resources/Documentation/about.md
new file mode 100644
index 0000000..b056bf7
--- /dev/null
+++ b/src/main/resources/Documentation/about.md
@@ -0,0 +1,273 @@
+The @PLUGIN@ plugin allows to import projects and groups from a remote
+Gerrit server into the Gerrit server where the plugin is installed.
+
+The imports are done online while both, source and target Gerrit
+server, are running.
+
+The user that does the import must be a member of a group that is
+granted the 'Import' capability (provided by this plugin) or the
+'Administrate Server' capability.
+
+Importing also requires a user/password for the source Gerrit server.
+This user must be able to see the entities that should imported.
+
+The data for the import is retrieved by accessing the Gerrit REST API
+on the source Gerrit server. Additionally project imports fetch from
+the repositories on the source Gerrit server. The git operations are
+done over the HTTP protocol.
+
+Imports are done in several steps:
+
+* do initial import
+* [optional] resume import as many times as you want
+* complete the import
+
+Until an import is completed, the imported entities should not be
+modified in the target Gerrit server, otherwise resuming the import may
+fail or even override modifications done in the target Gerrit server
+(e.g. change approvals will be overridden). But depending on what was
+modified, it may also just work.
+
+Imports are logged in 'review\_site/logs/import\_log' so that
+administrators can see who imported when which project. Imports do also
+send audit events.
+
+<a id="project-import">
+### Project Import
+
+The import project functionality allows to import (move) a project from
+one Gerrit server to another Gerrit server.
+
+<a id="project-import-process">
+#### Process
+
+A project import would be done in several steps:
+
+* do the initial import of the project
+* test on the target Gerrit that everything is okay
+* inform the project team about the project move and disallow further
+  modifications of the project in source Gerrit server (e.g. by
+  permissions or by setting the project state to read-only)
+* resume the project import to get all modifications which have been
+  done after the initial import
+* complete the import and if needed make project in the target Gerrit
+  server writable
+* inform the project team that they can now work on the project in the
+  target Gerrit server
+* reconfigure any third-party tools (such as Jenkins) to work against
+  the project in the target Gerrit server
+* [optionally] delete the project in the source Gerrit server using the
+  [delete-project](https://gerrit.googlesource.com/plugins/delete-project/+doc/master/src/main/resources/Documentation/about.md)
+  plugin
+
+Doing an initial import first and resuming the import later has the
+advantage that the downtime for the project team can be kept minimal.
+The initial project import may take some time, but the resume should be
+fast since it only needs to transfer the delta since the initial (last)
+import.
+
+<a id="project-import-preconditions">
+#### Preconditions
+
+Preconditions for a project import:
+
+* The parent project of the imported project must already exist in the
+  target Gerrit server.
+* User accounts must exist in the target Gerrit server unless auth type
+  is 'LDAP', 'HTTP\_LDAP' or 'CLIENT\_SSL\_CERT\_LDAP'.
+
+For auth type 'LDAP', 'HTTP\_LDAP' or 'CLIENT\_SSL\_CERT\_LDAP' missing
+user accounts are automatically created. The public SSH keys of a user
+are automatically retrieved from the source Gerrit server and added to
+the new account in the target Gerrit server.
+
+Gerrit internal users (e.g. service users) are never automatically
+created but must be created in the target Gerrit server before the
+import.
+
+<a id="project-import-commands">
+#### Commands
+
+Importing a project can be done via
+
+* [REST](rest-api-config.html#import-project)
+* [SSH](cmd-project.html) and
+* UI from menu 'Projects' > 'Import Project'
+
+Resuming a project import can be done via
+
+* [REST](rest-api-config.html#resume-project-import)
+* [SSH](cmd-resume-project.html)
+* UI from the list imports screen (menu 'Projects' > 'List Imports') and
+* UI from the project info screen ('Resume Import...' action)
+
+Completing the import can be done via
+
+* [REST](rest-api-config.html#complete-project-import)
+* [SSH](cmd-complete-project.html)
+* UI from the list imports screen (menu 'Projects' > 'List Imports') and
+* UI from the project info screen ('Complete Import' action)
+
+When doing a project import the project in the target Gerrit server can
+be created with a new name or under another parent project.
+
+<a id="project-import-steps">
+#### How the project import works
+
+The project import is implemented in such a way that it replays the
+actions that have been done in the source Gerrit server with preserving
+the original timestamps.
+
+A project import consists of the following steps:
+
+* creation of the Git repository and project in the target Gerrit server
+* fetch all refs from the source Gerrit server
+* [optional] reparent project in the target Gerrit server
+* replay all changes (changes in the target Gerrit server get new
+  numeric ID's)
+* import of groups for access rights on this project if they are
+  missing in the target Gerrit server
+
+Replaying a change is done by:
+
+* replay all revisions (create the change refs and insert the patch sets)
+* replay inline comments
+* replay change messages
+* add approvals (approvals for unknown labels are ignored)
+* add hashtags (hashtags are only applied if the importing user has
+  permissions to edit hashtags, e.g. if the
+  [Edit Hashtags](../../../Documentation/access-control.html#category_edit_hashtags)
+  global capability is assigned)
+* add link to original change as a new change message
+
+<a id="import-file">
+#### Import File
+
+At a point in time a project can be imported only by a single process.
+To protect a running import from other processes the import creates an
+import file 'review\_site/data/@PLUGIN@/\<target-project-name\>' and
+locks this file. In the import file an
+[ImportProjectInfo](rest-api-config.html#import-project-info) entity is
+persisted that stores the input parameters and records the past
+imports. The import file is kept after the import is done so that the
+input parameters do not need to be specified again when the import is
+resumed.
+
+<a id="resume-project-import">
+#### Resume Project Import
+
+Once a project was imported, the project import can be resumed to
+import modifications that happened in the source Gerrit server after
+the initial/last import to the target Gerrit server has been done.
+
+The resume of an import is only guaranteed to work if none of the
+imported entities has been modified in the target Gerrit server,
+otherwise resuming the import may fail or even override modifications
+done in the target Gerrit server (e.g. change approvals will be
+overridden). But depending on what was modified, it may also just work.
+
+On resume changes that have the same last modified timestamp in the
+source and target Gerrit server are skipped, unless the force option is
+set.
+
+The force option is useful if an import finished with warnings (in the
+error log) and the import should be resumed after fixing the issues,
+e.g.:
+
+* approvals for unknown labels have been skipped and the labels have
+  now been configured on the target Gerrit server
+* hashtags couldn't be set due to missing permissions, but the
+  permissions have been granted now
+
+On resume approvals, hashtags and change topic are always reapplied.
+This means that any modification of these properties in the target
+Gerrit server is overridden if the import of a change is resumed.
+
+<a id="complete-project-import">
+#### Complete Project Import
+
+Completing the project import deletes the [import file](#import-file)
+for that project. Afterwards it's not possible to resume the project
+import anymore. Also the project doesn't appear in the list of imported
+projects anymore.
+
+<a id="project-copy">
+### Project Copy
+
+Project copy is a special case of project import, where a project from
+the same Gerrit server is imported under a new name.
+
+To be able to copy a project the user must be a member of a group that
+is granted the 'Copy Project' capability (provided by this plugin) or
+the 'Administrate Server' capability.
+
+Please note, due the implementation doing a project import internally
+the user doing the copy must have an HTTP password generated.
+
+<a id="project-copy-commands">
+#### Commands
+
+Copying a project can be done via
+
+* [REST](rest-api-projects.html#copy-project)
+* [SSH](cmd-copy-project.html) and
+* UI from the project info screen ('Copy...' action)
+
+Resuming a project copy can be done via
+
+* [REST](rest-api-projects.html#resume-copy-import)
+* [SSH](cmd-resume-project.html)
+* UI from the list imports screen (menu 'Projects' > 'List Imports') and
+* UI from the project info screen ('Resume Copy...' action)
+
+Completing the copy can be done via
+
+* [REST](rest-api-config.html#complete-project-import)
+* [SSH](cmd-complete-project.html)
+* UI from the list imports screen (menu 'Projects' > 'List Imports') and
+* UI from the project info screen ('Complete Copy' action)
+
+When doing a project copy the project *cannot* be put under another
+parent project. But you can reparent the project copy after the copy is
+done.
+
+<a id="project-rename">
+### Project Rename
+
+By doing a [project copy](#project-copy) and then using the
+[delete-project](https://gerrit.googlesource.com/plugins/delete-project/+doc/master/src/main/resources/Documentation/about.md)
+plugin to delete the source project, a project can be renamed.
+
+<a id="group-import">
+### Group Import
+
+The import group functionality allows to import a Gerrit group from one
+Gerrit server to another Gerrit server.
+
+<a id="group-import-preconditions">
+#### Preconditions
+
+Preconditions for a group import:
+
+* If the group is not self-owned, the owner group must already exist in
+  the target Gerrit server.
+* Included groups must already exist in the target Gerrit server.
+* Member accounts must exist in the target Gerrit server unless auth
+  type is 'LDAP', 'HTTP\_LDAP' or 'CLIENT\_SSL\_CERT\_LDAP'.
+
+For auth type 'LDAP', 'HTTP\_LDAP' or 'CLIENT\_SSL\_CERT\_LDAP' missing
+member accounts are automatically created. The public SSH keys of a
+member are automatically retrieved from the source Gerrit server and
+added to the new account in the target Gerrit server.
+
+Gerrit internal users (e.g. service users) are never automatically
+created but must be created in the target Gerrit server before the
+import.
+
+<a id="group-import-commands">
+#### Commands
+
+Importing a group can be done via
+
+* [REST](rest-api-config.html#import-group) and
+* [SSH](cmd-group.html)