To get started with Halium, you'll need to get familiar with Repo and Version Control with Git.
To initialize your local repository using the Halium trees, use a command like this:
repo init -u https://github.com/droidian-bionic/android.git -b halium-9.0
Then to sync up:
repo sync
Now to build a system image:
./halium/devices/setup "halium_arm64" --force-sync --force-remove-dirty
./hybris-patches/apply-patches.sh --mb
export LC_ALL=C
export USE_CCACHE=1
source build/envsetup.sh
lunch "lineage_halium_arm64-userdebug"
time make -j10 e2fsdroid
time make -j10 systemimage