Fix build documentation

Standalone build information was omitted.

Change-Id: Ifcbbdb49f62d3797e9436286b78c0af9f03a00e3
diff --git a/src/main/resources/+Documentation/build.md b/src/main/resources/+Documentation/build.md
index 7b18329..12e6726 100644
--- a/src/main/resources/+Documentation/build.md
+++ b/src/main/resources/+Documentation/build.md
@@ -1,7 +1,48 @@
 Build
 =====
 
-This plugin is built with Bazel.
+This plugin is built with Bazel, and two build modes are supported:
+
+* Standalone
+* In Gerrit tree
+
+Standalone build mode is recommended, as this mode doesn't require local Gerrit
+tree to exist. Moreover, there are additional manual steps required when building
+in Gerrit tree mode (see corresponding section).
+
+## Build standalone
+
+To build the plugin, issue the following command:
+
+```
+  bazel build @PLUGIN@
+```
+
+The output is created in
+
+```
+  bazel-genfiles/@PLUGIN@.jar
+```
+
+To package the plugin sources run:
+
+```
+  bazel build lib@PLUGIN@__plugin-src.jar
+```
+
+The output is created in:
+
+```
+  bazel-bin/lib@PLUGIN@__plugin-src.jar
+```
+
+This project can be imported into the Eclipse IDE:
+
+```
+  ./tools/eclipse/project.sh
+```
+
+## Build in Gerrit tree
 
 Clone (or link) this plugin to the `plugins` directory of Gerrit's source tree.