ok whenever someone has a level up you press start and go to the level up screen. Hit the black button then the a button the "FLU" ( fake level up)-it'll show someone's head on someone else's body-so to FLU mission, you go to mission's level up screen and hit black and then a right after (like, really really fast afterwords) and you can pick feats and skills. To get a master skill, FLU and get the 2 skills (basic and improved), then RLU (real level up) and get the third, master level. Hope this helps.