Help figuring out my first belt

Okay so I just picked up my first chastity belt and could use some guidance on putting it on. Before you ask, the maker isn’t clear to me since I got this thing from craigslist. It’s a leather piece that functions as an actual belt… harness setup really. Here’s what has me puzzled: there’s a pouch at the front with a hole in it and a strap attached to keep things secure. Is that strap meant for my penis or is it for holding up my balls?