One loop at a time, just like everyone else.
I start out heading right, so it comes to the center from the left when I’m done threading. I never thought about it or considered the other way
I’m not sure how one could do it any other way, since to thread it buckle first would is usually difficult or impossible unless your belt is very and the belt loops are very long.
I honestly can’t remember noticing if women’s belts sometimes go the other way, like many tops, blouses, and jackets.
Threaded around from left front of hip so loose end to right of center and buckle to left when done.