It might help to watch this video to get a sense of how the looper works:    

It's essentially a four-track looper (you'll see we kept it simple), but you can overdub as many times as you like. You'll see the way we do drums in two parts. 

The companion app will definitely help select new songs, sounds, and settings. The surface of the instrument will have different tunings available, but the functionality of the buttons will not be a customizable feature.