Lay out two of the 2-by-4-foot sections of lumber exactly 4 feet apart from each other. Measure 24 inches from the inside of one piece of lumber with the tape measure and place the third piece of 2-by-4-foot lumber in the center of the other two pieces.
Place two of the 1/2-inch-by-3-inch boards on top of the 2-by-4-foot sections flush with the ends of the longer sections. Secure the thinner pieces of lumber to the top of the 2-by-4-foot sections with the hammer and nails. These nails should be hammered 1/2 inch away from the side of the structure.
Measure out exactly 12 inches away from the edge of the newly secured boards with the tape measure and mark the 2-by-4-foot section. Attach two more of the thinner 1/2-inch-by-3-inch lumber with the hammer and nails. Carefully flip over the structure because this side serves as the bottom of the pallet.
Place two of the thinner 1/2-inch-by-3-inch pieces of lumber at each one of the structures on top, setting them flush with the ends of the structure. Secure them to the structure with the hammer and nails. Finish building the platform by placing the remaining 10 pieces of 1/2-inch-by-3-inch lumber equal distances apart between the two edge pieces of wood. Secure them to the structure with the hammer and nails.