To prep the wood to build the shelving units, cut the pieces that will frame out the top and sides of the shelving units (Images 1 and 2). Cutting these pieces ahead of time will help the assembly go faster.
Cut the 1" birch plywood to 1x6s, then use a table saw to cut them down to 1x2s in order to use them as facings on the bookshelves (Images 3 and 4).
These shelving units were built to fit a cathedral ceiling; therefore the shelving units are going to be consecutively taller than the previous.
Starting with the shortest shelf, which is 30" high and 2' wide, lay down the two side pieces and use a framing square to mark each piece of wood (Images 1 and 2).
Since the first unit will be 30" high, and we want to the shelves to be evenly spaced, mark every 10" for a shelf.
Run a bead of wood glue along each of the lines (Image 1).
Immediately after running the glue, stand up vertically the piece of wood with the glue and the piece that is going to be the shelf and bring the shelf piece in perpendicular to the glue line (Image 2)
Use a nail gun on the outside of the plywood where the shelf and the glue meet and secure the shelf to hold the shelf to the side panel (Images 3 and 4).
Repeat this step two more times for the two additional shelves.
Also add 2" drywall screws for extra strength. It’s a good idea to pre-drill the holes so the screws will be drilled in below the surface of the wood (Images 1 and 2).
For the back of the shelf, use a 1/4" piece of birch plywood and staple around the edges every 6" to hold it to the shelves (Images 3 and 4).