To make this project easier, you can have the ply panel pre-cut at your local Bunnings*.
For our cut list, we ripped the ply panel to get a 400mm width. Then this was cut in half into 2 x 1125mm x 400mm lengths for the top and bottom of the unit.
We also had two lengths of 400mm cut from the 200mm x 2250mm offcut for the unit ends.
*Not available at all Bunnings stores.