if you've just made it into the legends league...
Nothing!!!! They do not even send a single message !!!! Not even to congratulate the winner!! I AM very disapponted!!!!
Any money involved?! And are the tournaments real or do you only match against equal ratings?
https://support.chess.com/article/2813-what-are-leagues-how-do-i-join-one
You just play normally and may never play anyone that is your division or league. There was a contest when it was first released, but that ended in early February. The site is working on some events for Legend league, that will have prizes, buy that's the only one that has plans for anything like that.