Usually the first strap is a single strap. Then the last 2 straps are connected at the top. Like others said, the extra strap is an "emergency strap". It is best to use the first and last one, like in the picture. You never want to use both the ones that are connected together. If you do, and one breaks, the other will break too and then your girth is gone. With using two that aren't connected, you'll have one strap still if one breaks while your riding. That said, all saddles are different. My saddle, the first two are connected and the last one is single. I still use the first and last one, but just check your saddle and use two that aren't connected.