Basses on an accordion are arranged according the so called "Stradella" system. There's much to say in favor of this Stradella bass lay-out, but it takes a while before you're comfortable with it. Many try to learn the basses by looking for bass tips or studying specific bass techniques.
These methods take a lot of time and aren't very efficient. On the other hand, accordion lessons can be very expensive and Accordion books are rarely meant for beginners. This piece of accordion software will help you to master the accordion basses. Not the hard way, but the fun way.