Currently Source of A16 QPR0 is buildable with December Security Patch
To get started with Android/Project-Sakura, you'll need to get familiar with Source Control Tools.
To initialize your local repository using the LineageOS trees, use a command like this:
repo init --depth=1 -u https://github.com/ProjectSakura/android.git -b 16-qpr0 --git-lfs
Then to sync up:
repo sync -c --no-clone-bundle --no-tags --optimized-fetch --prune --force-sync -j$(nproc --all)
. build/envsetup.shlunch lineage_$device-$buildtypem bacon