diff --git a/Documentation/developer-guide.md b/Documentation/developer-guide.md
index 82fedb0..6f809fd 100644
--- a/Documentation/developer-guide.md
+++ b/Documentation/developer-guide.md
@@ -21,6 +21,12 @@
 $ go install github.com/bazelbuild/bazelisk@latest
 $ export PATH=$PATH:$(go env GOPATH)/bin
 ```
+
+Make sure to initialize and update the git submodules:
+```
+git submodule update --init
+```
+
 You are now ready to build and test.
 
 ```
@@ -36,11 +42,12 @@
 Error in execute: Argument 0 of execute is neither a path, label, nor string.
 ```
 
-Make sure you are using python2. For debian users, the command
-is:
+Make sure you have `python` available in your PATH. Since Debian 11 and Ubuntu
+20.04 LTS (focal), there is no `/usr/bin/python` provided by default. You can
+install a package to provide a link to Python 3:
 
 ```
-sudo apt-get install python-is-python2
+sudo apt-get install python-is-python3
 ```
 
 Upon uploading your new CL, if you encounter a message related to a