I have recently added Doll sized Tennis Bracelets to the shop.
I attach the ends on first after I determine how many stones I need to wrap around the dolls wrist. It changes with the size of the stones. Then I twist the jump rings open and use them to hold the clasp on to the end I attached to the chain. I twist the jump rings closed, then tug on the ends to be certain they are good and secure.
These take a bit more effort to put on as you don't have a ton of room to work the clasp, but I did experiment with one that was a tad bigger but it didn't sit on her wrist nice.