To prepare the wood to build the shelving units, cut the pieces that will frame the top and sides of the shelving units (Images 1 and 2). Cutting these pieces ahead of time will help make assembly faster.
Cut 1" birch plywood to 1x6s, then use a table saw to cut them to 1x2s to use as shelving liners (Pictures 3 &4).
These shelving units were built to fit a cathedral ceiling; therefore, the shelves will be consecutively taller than the previous ones.
Starting with the shortest shelf, which is 30" tall and 2' wide, lay out the two side pieces and use a square to mark each piece of wood (Pictures 1 &2).
Since the first unit will be 30" tall, and we want 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, vertically lift the piece of wood with the glue and the piece that is going to be the shelf and bring the shelf piece perpendicular to the glue line (Image 2)
Use a nail gun on the outside of the plywood where the shelf and glue meet and secure the shelf to hold the shelf to the side panel (Pictures 3 &4).
Repeat this step two more times for the two additional shelves.
Also add 2" drywall screws for added strength. It's a good idea to pre-drill the holes so the screws are drilled below the surface of the wood (Pictures 1 &2).
For the back of the shelf, use a piece of 1/4" birch plywood and staple the edges every 6" to hold it to the shelves (Pictures 3 &4).