How do I edit stats and skills in UFC 3 carrer mode?

Hi guys! 

Today I've bought UFC 3 on Xbox One S and the thing is that I wanted to play career mode with my own fighter with custom skills and stats (I know there's no point in playing like that, but unfortunately I'm such a player like that). I don't know, what to do, because when I created my player and tried to import him to carrer mode the game told me that only his appearance will be imported and the stats and skills will be able to edit after I turn on some kind of mode. I don't really know, what kind of mode is that. Can you guys explain me what should I do to play career mode with my own player with custom stats and skills? Could you guys send me some kind of printscreen or video to help me with that thing?

Please help!!!