To get started with Android, you'll need to get familiar with Git and Repo.
To initialize your local repository using the YAAP trees, use a command like this:
repo init -u https://github.com/yaap/manifest.git -b fourteen --git-lfs
Then to sync up:
repo sync -j$(nproc --all) --no-tags --no-clone-bundle --current-branch
The source at YAAP is well configured for building.
source build/envsetup.sh
lunch yaap_device-user && m yaap