Hitman mastery question

So I am attempting to get all the trophies in hitman 1 ,2 and 3 as they’re all part of the bundled hitman 3 game, but my question is to obtain mastery on a level, can I just replay the stage and do a challenge or two at a time or does it all have to be done in one go? I don’t understand what mastery means is anyone able to explain this to me?