This video shows how to tie a Prusik Hitch. This knot is used to secure a tarp to a ridgeline. Any time you put a tarp over a hammock, a tent, or even a picnic table, this can be used to keep the tarp in place on the ridgeline.
For a complete guide to the basics of hammock camping, check out our Hammock Camping 101 article. And for more great how-to videos, go check out Black Owl on Youtube.