G'day Rick,

It's tuned like a mouthorgan (sort of). There's no choice of basses - just tonic bass and chord in and dominant out, so just beat out good time (or not at all). It can play its dominant key (mostly pushes - especially at start and finish - key notes button #4 or #7) or it related Dorian (mostly outs, key note button #4 outwards) or the related minor on the higher end (more outs again - key note #6 outwards) or the mixolydian ... or blues ... (starts on the #3 button out and has a fairly even mix).

Or you could shell out for a good instruction book in the style you like!

Regard(les)s,

Bob Bolton