Measure the area where you want to place your shelf. Measure 34” to 36” up from the floor (depending on how high you want your shelf counter to be. Use the level to draw a line at the height you want, ensuring that your line is completely level.
Cut the plywood to size, it should be no more than 18-20” deep. Paint and/or stain the wood. You can trim the edge with molding if you prefer. Allow to dry.
Install the metal shelf brackets into studs if you can using the level line that you drew in the first step as your guide to where the top of the bracket should be. If you can’t find any studs, use the heavy duty drywall anchors.
Lay the plywood over the brackets and fasten to the brackets from underneath with screws.