Playing on the bass side. Well, once you know what button does what, you can play on the bass side. Usualy it works like this. Find the bass key with the diviot in it. That is C. Go toward the front and your up a third (?) E. Go toward you and you have Cmaj chord. Go back one more and your have C minor, back one more C 7, one more and your on C dim.
That's for a 120 button box. Then when you go toward the top you have similar rows for g,d,a,e,b,f#,C#,G# D# and A#, going down you get F, Bflat and so on down to Bdouble flat. Usualy the smaller buttons drop the diminished Then some of the sharps and flats. You if you can play the haminca, you could play tunes on the bass side.
My 140 button bass has four voices on the bass side. The lowest note is an Ab at about 80 cps. Sounds like a 20' pipe in a pipe organ. Then you can add the voices in various combonations to sound like differant parts of the ochastra.
I wish I was worthy of my instrument. But in a few more years I might make it. :) I plan on going back for more lessons this fall.
Good luck. and Enjoy!