Howdy and welcome to the forum!
That type of halter, there are several different ways to make a halter out of it, but basically, you're making a "war bridle".
Here is a pretty crappy link to a picture of how it's put together. I'll try to remember tomorrow to go to the barn and get some better pictures of how to put it all together as I'm horrible at explaining things through text. It Doesn't Have to Be a War – America’s Horse Daily