Match your camper top to your pickup truck. Pickup bed dimensions will vary among manufacturers and models, and your top must fit those dimensions. Measure the length and width of the bed and the width of the bed sides where the top will rest. Check the weight limitations of your truck. Most tops are fiberglass or aluminum and not excessively heavy, but the weight of the top and contents of the camper will affect your truck. Your top should fit evenly and securely on all sides.
Get help to mount your camper top. Even if they're made of lightweight materials, most are still too much for one person to handle. Start by putting camper top tape on top of the bed edges. This comes in varying widths; choose one appropriate to the width of your camper top's bottom edges. Peel off the protective backing and mount it on top of the bed edges. Some manufacturers recommend a double thickness on the cab side. Tape will provide a moisture/air seal and help get a more secure fastening. Make sure the top is on straight; it should sit firmly before any fastening.
Fasten your camper top. Some styles come with locking mechanisms which fasten the top to the pickup bed. Some owners use sheet metal screws to fasten the top to the bed; others drill holes and install bolts (make sure the nuts are on the upper side, for easy access). You also can use C-clamps or special camper top clamps that fit above the top's sides and under the lip of the bed side, then screw tight with a bolt. Before you firmly secure fasteners, make sure the tailgate and top back window open and close properly.
