If you can’t find two trees, you could try placing two anchor branches in the ground instead. These trees should be roughly as far apart as your tarp is long.
Figure out which way the winds are blowing. Any “wall” of your tarp shelter should face away from the wind. Avoid putting your shelter in any areas that are low or seem like they could flood during rain storms.
Tie one section of the rope to a tree. Place it as high up the tree trunk as you would like the roof of your tarp shelter to be. Bring the other end over to the adjacent tree and tie it at the same level. Make sure the cord is as tight as it can be to ensure a strong ridge-line.
Make sure the tarp is equally hanging from both sides of the ridge-line to avoid problems.
Place a tent stake into the ground, near to the point the tarps corner while it is stretched out. Tie a length of cord between the tent stake and the corner of the tarp. Make sure this cord is tight and holds the tarp securely to the ground. Do the same thing for each of the other three corners of your a-frame tarp shelter.
Find two trees that are as far apart as your tarp is long. Tie one end of the rope around the trunk of a tree. Tie it at the height that you want the top of your shelter to be at. Tie the other end of the rope at the same level on the opposite tree. It’s very important that the ridge-line is as tight as it can be.
Your tarp may have holes pre-made along its edge. If so, you can thread the ridge-line through these for an easy way to join them together. Many tarps will have loops along the corners or edges that can be used to tie them to your ridge-line.
Most people recommend using a 45 degree angle for their lean-to. Try adjusting the angle to raise or lower the height of the shelter’s “ceiling”.
