Measure and write down the depth, width and height of the space where you want the new storage to be located. Take each measurement twice with a tape measure to ensure accuracy.
Make a detailed plan on graph paper with the measurements you took using each square on paper to represent 1 foot. Make a note of the dimensions for each panel that you will have to cut and the height and spacing of the shelves.
Mark and saw plywood to size. You will need enough plywood for two side panels, a top, a base and a rear panel, with enough left over for shelves.
Measure where the shelves are to be fitted to the side panels, and mark with a pencil. Measure accurately to avoid sloping shelves.
Route the inside of the side panels to accommodate the shelves. The routing should be horizontal and 1/10-inch larger than the thickness of each shelf.
Attach the side panels to the top and base panels with wood glue and wood screws, using the drill to make pilot holes for the screws. Lay the frame of the storage unit on the floor with the front facing down.
Apply wood glue to the edges of the rear panel, and place the panel on the frame, using a carpenter's square to ensure it is straight.
Secure the rear panel to the frame with wood screws, double-checking that the unit is straight with the carpenter's square beforehand. Once the rear panel has been screwed in place, stand the unit up.
Apply wood glue to the routed grooves in the side panels. Slide the shelves into the grooves, making sure they are firmly in place.