Extang Trifecta ALX Soft Folding Tonneau Cover for 2015-2022 Chevrolet Colorado / GMC Canyon (5'2" Bed)

Here's the short version. Follow Extang's install sheet (below) for your GM truck's exact bracket hardware and torque settings.

1. Set the cover on the bed. Lay the folded cover over the cab end of the bed, square, with its bulkhead seal on the bulkhead. Unfold it and slide it until the tailgate seal touches the tailgate with its first two fins, then fold it back up without moving it.
2. Clear the flange and clamp the front. If a plastic bed-rail cap hangs below the metal bed flange (Extang names 2004-2014 and 2021 F-150s and 2009-2019 Rams, but check any truck), trim just enough plastic for the clamp to reach the metal; never cut into the bed. Then slide each cab clamp to the bed rail, hook its jaw under the metal flange and hand-tighten until it touches, then two more turns. Not on a liner lip or the plastic cap, and no wrench.
3. Close the cover and mount the striker brackets in the stake pockets. With the tailgate open and both cab clamps tight, close the cover. On each side, pull the bed-wall hole plug, drop the tap plate down through the stake pocket and line it up with the hole, then run the 5/16"-18x1" bolt through the washer and bracket slot into the tap plate. Slide the backing plate up until it meets the bottom of the bed cap. A drop-in bedliner needs clearance holes for these fasteners.
4. Adjust the latches and rotary knob. Both latches and the knob leave the factory only partly tightened. Lower the rear of the cover, slide each latch until it catches its striker and lock it from underneath with the T-20 wrench. Leave 3/4"-1" of the driver-side cable through the barrel clamp, tighten the knob screws and the barrel-clamp set screws (2.5mm hex), then turn the knob to check both latches let go. Hand tools only, no power tools.
5. Make the final adjustment. Back off the striker bracket bolts or screws, push the closed cover firmly down (or pull the rear bow down) onto the rail and tailgate so the brackets move down, match both sides and retighten. Use the torque Extang's sheet gives for the stake-pocket bracket.
6. Fit the tethers and recheck. The tethers come looped over the cover bow. Slide each tether clamp onto the bed rail as far up as it goes and hand-tighten the knob, both sides. Lift the corners gently to check the cover is latched, and re-tighten the cab clamps and tethers after your first week of driving.