TE20 training calculator

[mindsetglitched]

Hello guys, i am a new player, just started last season but at the very, very end since i only play 1 league match, and i have been looking for guides and tips, but i cant find the ones im looking for.

So what i want to know is that, does the training ground has anything to do with players development or it only depend on the class (or something that looks like a whistle, i dont quite remember about the names) of the training and training levels?