If you don’t know a butcher like me, buy a piece of meat (I have beef), first cut into strips across the fibers and turn on the meat grinder. The ratio of meat and fat in meat is 70*30 80*20 (meat/fat), unfortunately, the burger has never been considered a dietary dish and is unlikely to become one.
The main thing in it is chicken, I used to think that the sauce (naive)
Meat can be seasoned only with pepper, not salt, otherwise you will get a “sole”. Salt only at the end of cooking cutlets. Beat the minced meat like dough, saturating it with oxygen, lifting it from the bottom up and not rolling it into a ball.