To make this project easier, you can have your timber cut to size at your local Bunnings.
We had our 2400mm x 1200mm x 17mm form ply cut to:
Take one of the long lengths of timber and measure out the positions for the shelves. This bookcase will include a fixed shelf in the centre and four other shelves. Measure and mark the halfway point, which is where the fixed shelf will go. Square this mark off with a pencil line. Measure and mark the positions for the other shelves.
Line up the other unmarked length of long ply so that it's flush with the marked piece. Transfer the marks for the shelves onto the second piece of ply. This will ensure the shelves are straight and even when you install them.
Once you've marked the shelf positions on both side panels, lay them flat together on the bench and draw straight lines across the panels.
Use the square to mark the positions where you'll drill holes for the shelf supports. You'll need two supports for each shelf.
When drilling the holes for the shelf supports, you need to be careful not to drill too deeply. A good tip is to wrap masking tape around the 3mm drill bit at the level you want. Now you can safely drill all of the eight holes for the shelf supports.
Two of the 565mm pieces of ply are for the top and bottom of the cupboard. Starting with the top piece, make sure it is flush with the end of the side panel and pre-drill holes using a 5mm bit. Then screw into place using 45mm screws. Attach the other side length panel to the top piece the same way. Then you'll need to add the bottom piece of ply in the same way. It's a good idea to use corner clamps to secure the frame while you're working or get some help from a friend to hold it steady.
Once the frame is complete, sand it all over with the orbital sander and 180 grit sandpaper for a nice finish. Make sure you sand the shelf edges as well to remove any splinters.
Wipe the bookcase down to remove any dust before you start painting. You'll need to use masking tape where you're cutting in with a paint brush to ensure the lines are straight. Then use a roller to paint the larger areas. Apply as many coats as needed. It's a good idea to give it a light sand between coats.
Once the paint is dry, flip the bookcase over to attach the back. Make sure the ply is flush on both sides, then hammer the 25mm soft sheet nails into place. Once the back is secure, use a router to remove any excess. Once the backing is trimmed to size, secure it with more nails.
Give the shelves a quick sand and then wipe away any dust. Apply wax to the shelves, which will help to protect them and give them a great finish.
Insert the shelf supports into the drilled holes, then place the shelves on top of them.