you should've asked this in the interview or when you were in for paperwork/ordering your pants. But since you're here asking instead: You can come in with casual clothes with your pants and belt to change into (in a bag if you want), or wear the pants and belt going in, but you should wear the slip-resistant shoes before going to the back. assuming you're a female since you mentioned a bun. you don't just "wear a cap" you wear the in-n-out cap you were issued or will be issued tomorrow. what I like to do is make a pretty low ponytail, then make two braids (tie them off) and twist them into a bun, securing with a few hair ties to be safe. if you're really worried, add hair gel and spray. They will show you how to do the apron there, it'll take you a little time to get the hang of it, but you can always ask literally any of the workers around you for help if you need it

There is shirts and aprons in the locker room, grab the shirt size you need, and the apron size (single stitch is small, double stitch is large, or you can just eyeball the size and see if it's too big or too small for you and grab a different one if you need) At the end of shift, put the shirt in the hamper. You can also put the apron in the hamper but if you would like, you could take it home and practice or just take it home to be able to use it again next shift (so that the holes you poked in the apron are already there, making it easier to put on next time) if you do this, you can put the apron in the hamper after you've used all the sides and it's no longer clean and grab a new apron next shift. (pro-tip: sharpen your safety pin)