How to Construct a shelter out of tarp, string, and trees
If you ever find yourself stranded in the woods, then making a shelter is one of your biggest priorities. ITS Tactical created this detailed and approachable video on how to rig a shelter in woods out of only a tarp, a ball of heavy-duty string, and four metal tent-posts, three items that anyone, wilderness inclined or not, should keep in their car at all times. It goes over the necessary knots in great detail, and should make it unnecessary for any of us to sleep unsheltered outdoors again.
Step-by-step written instructions can be found here.