To get started with Android/XAOSP, you'll need to get familiar with Source Control Tools.
To initialize your local repository using the XAOSP trees, use a command like this:
repo init -u https://github.com/XAOSP/android.git -b 14 --git-lfs
Then to sync up:
repo sync
Build
source build/envsetup.sh
Breakfast device_codename
mka x