Extra weight classes

Hello, played the game for a few days. Ended up buying the extra weight classes, started a new game. I see the extra weight class rankings but when I look for amateurs, the extra weight classes don’t show up. How can I get fighters in the extra weight classes I paid for? Or is the only way to become undisputed and move up to those classes?

Amateurs is just set as the usual ones mate, professional weigh classes you will have all 16 and will be able to sign pro fighters for all 16 weight classes. When your amateur turns pro for example if they are a heavyweight, they can potentially turn pro as a cruiserweight, if they are a welterweight amateur they can potentially turn pro at super welterweight etc.