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Raise the garage door manually to its highest point of travel. Use a level to mark the highest point on the wall above the door, ensuring it is centered. Measure and mark the locations for the wall mounting bracket, which will hold the end of the opener rail closest to the door. Use a drill/driver and an appropriate drill bit to create pilot holes. Secure the wall mounting bracket to the wooden header (the structural beam above the garage door) using strong lag screws. Lift the fully assembled opener rail and motor unit, using two ladders for support. Attach the end of the rail to the newly installed wall mounting bracket, securing it with bolts and nuts. Use C-clamps to hold the rail in place while ensuring it is level before final tightening.