Most people recommend feeding exactly as the breeder did for the first few meals to ensure that the snake will eat in your care. I don't keep ball pythons, so I don't have enough experience to know what the best course of action will be for you, but in my opinion it wouldn't hurt to try f/t first as long as it is warm enough and you are minimizing stress. I think dakski also has a good step by step post for preparing f/t somewhere on here, so it might be helpful to find that.

In general for offering the f/t food though, if/when you do: you can wait until he's out and exploring at night, but if he tends to freak out and flee once you open the enclosure that might put him off eating. You'll probably be more successful offering while he's in his hide, that way he will feel nice and secure, and it will appeal to his ambush instincts. Just wiggle the mouse at the entrance and let him come to it, poking it in there might scare him. If he doesn't take it, you can leave it in overnight and remove it in the morning if it's still there. I would wait a week before offering again. Good luck!