To get started with Android/ProjectLlama, you'll need to get familiar with Git and Repo.
To initialize your local repository using the CyanogenMod trees, use a command like this:
repo init -u git://github.com/ProjectLlama/android.git -b jellybean
Then to sync up:
repo sync
Now set up the build environment
source build/envsetup.sh
Finally, to build do
brunch