Dont know how to talk to my crush

Hi guys, so im 18 bi in the closet and i have a pretty big crush on one of the guys in my school, the problem is that im not in any of the classes with him and i beraly know him at all, we used to be in gym class but i didn't talk to anyone at that time, so how do i talk to him now? P.s i dont know if hes gay or not but he has a pretty gay voice