Support the bed so that it is level and square. The bed does not have to be removed from the truck to perform this installation. Just be sure it is reasonably flat and not mounted in a twisted position. First, remove the tailgate, hinges and chain assemblies. Place some masking tape over the stock lower hinge attaching location on one of the bedsides. Reinstall the hinges and the new tailgate and make sure it is aligned to your satisfaction.