@ApolloX1209 basically, when he do things he gain exp (i don't know from what basis the amount gained vary) when he do the same thing several time he gain less and less exp for that thing.
He can write either the skill he want to gain or what he want to be able to achieve, in the first case he gain that skill, in the second case he gain different skills thats gonna allow him to achieve that.
I think, but i'm not sure at all, that he can chose the amount of exp put into learning new skill and the more exp he put, the better he'll become. For exemple if he put 100 exp he'll gain the memories of a normal cook, for 1000 exp he gain the memories of a 5 star cook and for 10000exp he gain the memories of the best cook in history.