Hold a 2-by-4-inch board vertically against a ceiling joist at the edge of the ceiling so that the top 2 inches of the board overlap the wood of the joist. Use an assistant to hold the board in place and nail the board to the joist with a hammer and two or three 10d nails.
Nail a second board to the joist, same as the first, but positioned 10 inches away from the wall.
Nail a third 2-by-4 board to a joist 4 feet further down the wall from the first board you installed, positioned at the edge of the ceiling.
Nail a fourth board positioned 10 inches out from the wall on the same joist as the previous board.
Cut four pieces of 2-by-4 board with a circular saw, each piece 14 inches long.
Nail the 14-inch-long pieces of 2-by-4 board between the vertical 2-by-4, on the inside facing edges of the boards (so that they face each other). Place two of the boards so they're even with the bottom edges of the vertical boards. Place two of the boards 2 feet up from the bottom edges of the vertical boards.
Place the 1-by-10-inch boards between the vertical boards, with the ends resting upon the horizontally place boards. Nail the 1-by-10-inch boards onto the 2-by-4 with 10d nails.