Why is it hidden? I don't get it.

Since I invited some of my friends to play, why it's working like this?
New players are very lost for this aspect of the game, even when every stats counts and maybe they wouldn't choose a specific profession since they would like to rob more or whatever.

Even broker or dealer, since they are new. Which stats they get bonuses from robbing? More str? more resist?
Not even the game guide helps with it...