Lean-To with Side Walls (Ridge Line)
To set this up you will need a ridge line, two guy lines, and four stakes. Start by dividing one side of the tarp into quarters and then loosely attach the two inside quarters of the tarp to the ridge line, stake down the two lower corners, attach guy lines to the two upper corners that were not attached to the ridge line and run them out creating side walls. You can create more room by adding a hood pull. Lash a line onto the hood, clove hitch it on an elevated pole and anchor it to the ground with your preferred rigging.
Lean-To with Side Walls Long (Ridge Line)
You can rotate your tarp and try it the long way. Again divide one side of the tarp into quarters and then loosely attach the two inside quarters of the tarp to the ridge line, stake down the two lower corners, attach guy lines to the two upper corners that were not attached to the ridge line and run them out giving you side walls. If you are going to try this configuration then I would definitely suggest adding the hood pull to add more room underneath.
Lean-To with Side Walls (Poles)
Now let’s set this up with poles, to do so you will need two poles, four guy lines, and six stakes. Start by staking down the two lower corners, on the peak side of the tarp attach your poles to the two inside quarters of the tarp and run out the guy lines, then attach another two guy lines to the outside corners of the tarp and run them out using you preferred rigging. If desired add a hood pull to add more space.
Lean-To with Side Walls Walls (Poles)
Alternatively rotate the tarp 90 degrees and stake down the two lower corners, on the peak side of the tarp attach your poles to the two inside quarters of the tarp and run out the guy lines, then attach another two guy lines to the outside corners and run them out using you preferred rigging. Space will be limited so add a hood pull for more space.
Links:
Setting up a tarp with poles
http://plighttofreedom.com/trekking-pole-tarp-setup/
A Comprehensive Guide to Tarp and Tent Guy Lines
http://plighttofreedom.com/guy-lines/
Tent Stakes & How to Use Them
http://plighttofreedom.com/tent-stakes/
3 Tarp Ridgelines: Tied, Toggled & Hardware
http://plighttofreedom.com/3-tarp-ridgeline…toggled-hardware/
5 Knots You Need to Know