Saw three 2-by-6-by-96 inch lumber boards into two 76-1/2 inch long side rails and two 37-1/2 inch end rails; two 2-by-4-by-96 inch boards into two 73-1/2 inch support cleats; and six 1-by-3-by-96 inch furring strips into 12 37-1/2 inch slats.
Butt the end rails within and perpendicular to the side rails, forming a rectangle. Secure each joint with wood glue and 2-1/2 inch screws.
Glue the support cleats into the frame, along the side rails, flush with the bottom edge. Screw them into place using 2-1/2 inch screws spaced every 6 inches.
Lay out the furring strips across the support cleats and secure them with 2-inch nails. There should be approximately 4 inches between each of these slats.
Drill a hole in each corner of the top of the frame, in the 2-by-6 inch rails, and install a lag eye bolt in each hole.
Install eye bolts into the ceiling joists or rafters above where the bed will be. If you want to secure the bolt from the opposite side, get eye bolts that are slightly longer than the thickness of the joists to secure with a nut. If you simply want to install into the wood, you can use lag eye bolts. Pre-drill the necessary holes to avoid splitting the wood.
Hang the bed using 6 feet of chain attached to each corner of the frame and the ceiling joists with quick links.