Seriously, watch the youtube video I posted. It's really easy.
Cut the paper so it wraps all the way around the box with a little overlap.
Cut the ends so the paper extends about 2/3 the way over the ends when you fold it down.
After you tape the paper so it wraps around the box (open ends), fold down the first end and tape it to the end of the box. When you do that, the ends of the paper will naturally make triangles. Crease them, then fold the triangles across the ends and tape them down. That will create another triangle on the remaining paper. Fold the top of that triangle down so that it covers the end, but doesn't extend over the edge of the box. Tape it down.