My fighters are training but no xp?

Not necessarily sure how to gain xp, during the tutorial I did what it asked but it got to a point after clicking gym where nothing popped up, only way I get XP is from fights. Training does nothing. Anyway to fix? I’ve tried making a new save but it dosent work.

Little tip if you want more exp. The more you leave the exp there and don’t use it, it grows a lot quicker. For example, your fighter has just fought he now has 4839 exp, he fights again, 7283, again 13476, again, 23827. The higher the number you leave there, the bigger it jumps in exp.

I spent the entirety of my time on this game at the start upgrading as soon as I could. I like to now let a fighter develop maybe 15-20 fights usually accumulates to a minimum of 50,000 exp.