Create a new working directory for your /e/ OS build and navigate to it:
mkdir e-build-gsi; cd e-build-gsi
Initialize your /e/ v1-q branch workspace:
repo init -u https://gitlab.e.foundation/e/os/android.git -b v1-q
Clone the modified treble manifest to local_manifests:
git clone https://github.com/netbospl/e-treble-local_manifests.git -b v1-q-trebleonly-v2 .repo/local_manifests
Sync repos
repo sync --force-sync -j$(nproc --all)
Finally, start the build script:
bash treble_build_los/buildbot_treble.sh
Be sure to update the cloned repos from time to time!