Stand two planks of 77-inch 1-by-6 lumber up on their 1-inch edges, 40 inches apart. Fit two planks of 40-inch 1-by-6 lumber between the ends of the 77-inch planks, making a rectangle frame. The 77-inch planks are the side rails of the bed base and the 40-inch planks are the head and foot of the bed base, which is twin size.
Glue the side rails and head and foot planks together and set into corner clamps to let the glue dry. Fasten the bed base together with four 1 3/4-inch screws driven evenly through the side of the rails into the ends of the head and foot planks.
Measure down 3 inches from the top of the side rails and position a 75-inch plank of 1-by-2 lumber along each side rail. These are the support planks for the bed slats. Secure the support planks to the side rails with 1 3/4-inch screws driven every 8 to 10 inches along the length of the support plank.
Position four 80-inch planks of 2-by-4 lumber upright against the side rails, flush with the head and foot of the bed base. These are the leg posts for the bed. Have a helper assist you to lift the bed base 10 inches off the ground and then clamp the legs to the bed base with G-clamps at this height. Check that the base is level and adjust if necessary.
Drill four pilot holes, sized for the shaft of 2 3/4-inch lag bolts, through the side rails into each of the leg posts. This will keep the outside of the leg posts unmarred by screw holes.
Secure the leg posts to the bed base with 2 3/4-inch lag bolts through the side rails into the leg posts.
Miter the ends of two 77-inch planks of 2-by-2 and two 46-inch planks of 2-by-2 lumber to 45 degrees using a miter saw.
Glue the mitered ends of the planks together to form a rectangle, which is the canopy for the bed frame. Set the canopy into corner clamps to let the glue dry.
Secure the canopy together with two 2-inch wood screws through each of the mitered joints.
Climb a ladder and have a helper assist you in raising the canopy up onto the ends of the leg posts. The corners of the canopy should be flush with the corners of the bed posts.
Secure the canopy to the top of the bed posts with two 2 3/4-inch wood screws through the top of the canopy into each leg post.
Evenly space 30 planks of 1-by-2 lumber across the bed base, with the ends of the slats resting on the support planks on either side of the bed rails. There should be 1/2 inch between each slat.
Fix the slats to the support planks with 1 3/4-inch wood screws through each slat end into the support planks.