add comment and link to the aomp_common_vars file
@@ -69,7 +69,7 @@ for other environment variables that you may override including repo names.
BUILD_TYPE Release
```
-Many other environment variables can be set. See the file aomp_common_vars that is sourced by all build scritps.
+Many other environment variables can be set. See the file [aomp_common_vars](amd_common_vars) that is sourced by all build scritps. This file has the names of the branches that make up the release that is in development. You can override the appropriate environment variable if you want to test your source build with a different release.
You can override the above by setting by setting values in your .bashrc or .bash_profile.
