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 git://github.com/ProjectSakura/android.git -b 12
Then to sync up:
repo sync --current-branch --force-sync --no-clone-bundle --no-tags --optimized-fetch --prune -j `nproc`
You can use your Lineage OS trees to build Sakura without any changes.
. build/envsetup.sh
lunch lineage_<devicecodename>-userdebug
mka bacon -jx