Measure your truck bed and purchase a set of plans that will fit your bed size. Your new set of plans should indicate the approximate weight of the finished camper, so be sure your truck can handle that weight by consulting your truck owner's manual. When you get your plans, be sure to read them carefully before you begin building.
Put the frame together. Assemble the two side walls, attach them to the floor material (usually plywood), and then connect them with the roofing joists.
Install insulation in the openings of the frame, and then install interior and exterior siding. If you're going with a simple construction, your camper siding may consist of basic plywood; for more expensive and elaborate versions, you may use aluminum or fiberglass siding, much like the professionals use. As you install these items, be sure to account for the doors, windows and vents you are going to add later.
Place vents, windows and the door in their proper position. Seal them in using caulk or another strong bonding material.
Seal your camper's edges with caulk, weatherproofing material or basic aluminum molding. Depending on your materials, (like if you're using plywood, for example) you may need a roofing sealant for the top.
Install interior features such as electrical outlets and lights, kitchen sink and stove, beds, table, storage areas, bathroom features and flooring.
