It seems that some folks are new to C system CBA and are a bit unsure as how to proceed with fingering. I pointed some members in the direction of the Swiss player, Jean-Yves Sixt, who has posted free lessons on You Tube. Whilst his lessons are invaluable, his technique is based on the French system which tends to require frequent use of the little finger. That can be difficult to master, especially for more mature students, or converts from PA.
The attached clip is not exactly an instructional video, but there are several good shots of Gino Daeder's right hand technique. This is typical of the Italian CBA fingering, particularly in Emilia Romagna and surrounding areas, where they play accordions which are basically the same spec as those in France (stepped "mushroom" bass buttons, and treble couplers mounted on the rear of the treble keyboard), albeit with different tuning, and more usually 4x2 rather than 3x3 French bass arrangement. There were pages of discussion on this matter on the forum some time ago, so I'll not go into it again.
If you watch the shots that concentrate on his right hand you'll see him make frequent use of his thumb, mainly on the first and second rows. His little finger is used occasionally, but not as often as it is by French players.
This was the style of playing I started off learning, but I later decided it wasn't "French" enough, and I switched to one of their methods. With the dubious benefits of hindsight, advancing years, and osteo arthritis, I would have been better sticking to it, as that little finger of mine never really made it as a major player in the French League. I've since began to work on my playing in an effort to get back to the fingering I started with, as I'm finding difficulty getting all my fingers to work properly after a long layoff from playing.
Just something to consider for those of you who might be struggling a bit (like me).
Finally, the trivia on Gino Daeder is that he is/was also a professional flautist and sax player. Don't think he's retired just yet. https://www.youtube.com/watch?v=4LyJsvgXZtI
EDIT:- Player's name is Gino Daeder, and not Bruno. Bruno was our last dog's name!