The top ends, the ends nearest the neck, are held together with a heavy juniper bark rope. The rope is laid out flat, and the ends are pushed into the rope materal, wrapped around the rope once, and reinserted. The rest of the cape just hangs free. I've made several of these and they can be made in a couple of hours. They are quite warm and dry.
Rain just runs off.
The biggest problem with them is ticks. My sources argue both. Just a quick pointer. Soak the Juniper bark you are using for rope. It is much easier to counter twist.