I tried it. Seems very basic.
That line of buttons underneath the instrument name, 1-5.... I assumed that was for layering different audio tracks. Unfortunately, they're just 'quick-access' buttons so you can quickly change between instruments on the *same* track whilst recording.
You basiclly have a few 4 present 'backing tracks' for each musical style, which each consist of a drumbeat, a bassline and a backing melody. You can switch between them as the song progresses, and you can switch the individual beat, bass and baking parts on and off - but you can't mix and match (say, bass line b with drum track a).
On top of that you have a single melody track - in which you can play one instrument at a time