Measure 77.5 inches across the wall. This measurement marks the length of the loft bed. Place a Billy bookcase perpendicular to the wall. Set a second bookcase next to the first. The shelves on each side should face out: one towards the room and one towards the center of the bed area. The bookcases measure 79.5 inches tall, which places the bed a little over 6 feet off the ground. Each bookcase measures 31.5 inches wide, and will provide support for the bed.
Set an Odda bed frame on top of the shelves. The Odda frame has a platform design with an exposed front and back. Flat wood panels on each end act as the legs and support. Arrange the bed frame so that the panels overlap your Billy bookcases on either end.
Sink a 2-inch wood screw into the flap on the end of the bed, driving the screw through the bed and into the bookcase. Drive the wood screws through every 2 inches around the flap and repeat on the opposite end.
Attach the Billy bookcases to the floor with L-brackets. Set one bracket on the end of the bookcase and screw into the shelf and floor with 2-inch wood screws. Attach 2 L-brackets to each end of the bookcases. Screw two L-brackets onto the front of each bookcase for extra stability.