Things will look much better in the morning! No wonder you're struggling; you'll be so much happier if you join your binding along a straight area of the edge, not at the point. Then I think the tutorials you've been watching will make a whole lot more sense to you. Can you cut some more binding strip so that you can join a new piece along one of the sides and get it set up so that you have about 12 inches of straight edge to do the final join? It's tricky enough to get those points right without trying to join the ends there too.