Nissan Frontier XSB/SB Electric Retractable Truck Bed Cover

The Bedlocker is designed to carry rainwater from the cover into the canister and then out through the drains. Most truck models have standard OE drain holes or plastic/rubber access ports in the front of the truck bed. Check to make sure your truck has the OE drain holes so that drilling into the sheet metal is not required. If drilling is necessary, be sure to check the underside of the truck bed for the best location. The holes should be located near the side and as far forward as possible. Use a drill bit suitable for sheet metal (such as a taper drill or step drill). Drill drain tube clearance holes at 3/4” (19mm). This will need to be done before installing the cover.
The BedLocker also offers an optional wire harness (part # BL1120) to manually operate the tonneau cover from inside the cab of your truck. This harness is designed to plug into the custom-built electronics control box. Simply run the wire to the cab and attach under the dash in a suitable location.
STEP 1: REMOVE CONTENTS & PLYWOOD PACKAGING
Remove the canister and top cover from the box. Remove components from inside the canister. Perform a quick inventory to insure all parts are there. Using the wrench or socket remove the 2 bolts holding the plywood packaging supports on the ends of the canister. Discard plywood packaging supports and bolts. Locate the rail guide bolts in the hardware pack and install them in the two holes where the packaging bolts and plywood were just removed. Repeat on both ends of the canister.
STEP 2: INSTALL WIRING HARNESS
(If the optional wire harness Part# BL1120 is used, you may want to tape it to the main harness to ease having to pull them through the stake pocket separately). From inside the truck bed push the long wire harness end without the plug through the stake pocket on the drivers side of the truck and out the underside of the truck bed box. Leave a couple of feet of slack inside the box for mounting the electronics. Route the wire harness under the truck and to the battery in the engine compartment. Attach the fuse holder to the end of the Red/positive wire. (Do not attach to battery yet) Secure the harness with wire ties provided.

Source