I asked a similar question
here and got an answer that worked for me: eyehooks.
I put 2 eyehooks on the back of each panel (maybe 12" down from the top) and then put 2 regular hooks on the wall. If you're mounting them straddling the corner and built 2'x4' traps, then you can put the wall hooks 15" from the corner (worked for me anyway - best to test it yourself.).
Once I had all the hooks in place, I laced a zip-tie through the eyehook and closed it, leaving plenty of slack. I then had someone hold the panel up while I hooked the zip-ties over the wall hooks...tightened the ties down and boom: snug against ceiling and walls.