Extang Trifecta Signature 2.0 Soft Folding Tonneau Cover for 2007-2013 Chevrolet Silverado 1500 / GMC Sierra 1500 (5'8" Bed, with Cargo Management System)

Here's the short version. Follow Extang's install sheet (below) for your truck's exact clamp positions and hardware.

1. Set the cover in place. Lay the folded cover over the cab end of the bed, unfold it, line it up at the cab and the tailgate, then refold it without moving it. If a plastic bed-rail cap hangs below the metal flange, trim it back with a utility knife so the clamps reach metal; never cut the bed.
2. Fit the bracket kit. On a bed with a factory cargo rail system, add the clamp plate, washers and screws to the cab and tailgate clamps as the sheet shows, and torque them to 65 in-lb (7.3 Nm). Don't overtighten.
3. Tighten the front clamps. Seat each Jaw-Grip cab clamp under the metal bed flange (not the bedliner lip or a plastic cap) and turn it by hand until it touches, then two more turns. No wrench, and don't overtighten.
4. Close it and latch the rear clamps. With the tailgate down and the front clamps tight, unfold the cover fully. Swing each rear clamp down out of the cover rail, slide it at a slight angle as far out toward the bed rail as it goes, then pull it straight down and let go so it hooks under the metal flange. Latch both sides.
5. Attach the tethers in the cargo rails. Open the cover and pull the end cap and any tie-down cleats off each cargo rail. Slide the supplied block into the rail, pass the tether knob through its lock washer and the tether bracket into the block, move it up to the front bow and tighten the knob so it can't shift or lift. Refit the cleats and end caps.
6. Recheck after a week. Re-tighten the front clamps and tethers after your first week of driving, and check them now and then. To drive folded, stow the rear clamps in the rail before you fold the second section, fold it to the cab and buckle both straps.