How does the accordion model work?

If you mean the bass {left hand} side of a piano accordion, like this: There is a system to it, it goes in 5ths and 4ths, you can play 3 chord songs without moving your hand. read more

Actually they are not all chords (this will depend on accordion type). The type that has many round buttons actually have two rows of bass notes to play with the chords; an alternate and root note. The other four rows are actually different chords; major, minor, seventh and diminished. read more

If you mean the bass {left hand} side of a piano accordion, like this: There is a system to it, it goes in 5ths and 4ths, you can play 3 chord songs without moving your hand. The right hand side is just like a piano, white keys are key of C, the black keys are the other 5 notes of the western scale. read more