See diagram in TM 9-2320-280-24-P1 figure 235.
Each side consists of a long strut #33, a short strut #38, an outer tube #31 and an inner tube #37. The other parts are clamps and rubber seals. The outer tube should be on the upper strut, which is the shorter one mounted to the rear hatch, and the inner tube should be on the lower strut (longer one) mounted to the tub inner fender bracket. Once you assemble the struts together, you will have to open the hatch as far as possible. BE VERY CAREFUL!!! Hatch is very heavy and it can crush you when in the air unsecured! Be safe!