jumping and all purposes have 3 straps for the girth to attach to, two are on the same 'panel' I guess you could call them? and the other is on its own.
Like what CWAC said, one buckle goes up on the one with two and other on the single. The single is there incase the other one breaks for safety incase you are jumping/galloping, the girth will stay on (but only be attatched to one strap on that side

)
I think once they break they are very hard to replace which is why you should really take care of them.
umm I hope that makes sence?!