Remove the wooden shelf from the cabinet along with any screws or small shelving holders that may be attached to the cabinet's side panels. Locate the shelf's left and right sides and measure 1/2-inch inward on both sides with measuring tape. Use the pencil to draw a straight line from the back to the front of the shelf that is parallel to the shelf's left and right sides.
Cut the two shelving sides with a table saw to remove 1/2-inch from each side of the shelf, removing 1 inch from the shelf's width. Sand the freshly cut sides to remove any splinters and cracks.
Separate the sliding tracks from the brackets. The brackets form the base of the sliding device. Take the brackets and set them on the cut sides of the shelf. Install them on both sides of the shelf with a screwdriver and 1/2-inch screws. The brackets have small pilot holes for inserting the screws.
Open the cabinet where you want to install the sliding shelf. Determine how high or low the shelf should be and mark the inside of the cabinet. Take one track and place it up against the inside panel of the left side. Place the level alongside the track until it is even. Take 1/2-inch screws and insert them into the installation holes in the track. Screw them into the cabinet side panel to secure the track. Repeat the step with the right-side panel and the second sliding track.
Insert the sliding shelf into the tracks installed on the inner side panels of the cabinet unit. Slant the shelf at an angle and apply some pressure. You will hear a click once the brackets are attached to the tracks.
Place the storage rack on the sliding shelf. If possible, attach the storage rack to the shelf with 1/2-inch screws and the screwdriver. Use larger screws if the bottom of the storage rack has a thickness of more than 1/4-inch. It is optional to attach the racks to the sliding shelf so forgo this step if you want to keep it unattached.