To get started with TeamJB/CyanogenMod JB build, you'll need to get familiar with Git and Repo.
To initialize your local repository using the TeamJB trees, use a command like this:
repo init -u git://github.com/TeamJB/android.git -b jellybean
Then to sync up:
repo sync
After the initial sync sync once more so that the local_manifest.xml will be picked up.
After that you need to get proprietary CM bits:
./vendor/cm/get-prebuilts