Find the L-shaped metal brackets as well as the 2 remaining slide pieces. Fit a bracket into 1 end on each slide. The brackets easily slide into the frame track. The free ends of the brackets will attach to the cabinets with screws. To make sure the bracket is placed correctly, test the frame pieces by fitting them inside the cabinet. Place the slide frame pieces inside the cabinet. Push the brackets all the way to the back. The frame pieces should be flush with the bottom edge of the cabinet and rest against the side walls. If you are using undermount or center mount slides, place the frame pieces on the cabinet’s bottom. The frames need to be level from front to back. To check this, set a carpenter’s level on top of the frame. Reposition each frame as needed until the leveling tool is even from left to right. When using a bubble level, for instance, the bubble will move to the center of the level. Mark where the frames rest on the cabinet. You can draw directly onto the cabinet with a pencil. Create the lines right over the ends of both frames. Then, mark the spots where the brackets and rails will be screwed in place.  Each bracket has 2 screw holes to mark. The rails will have at least 1 hole at the opposite ends. Make sure the lines are dark enough to see as you secure the rails. Drill into the spots you marked earlier. These holes prevent the screws from breaking or cracking the wood. Use a drill bit about 2⁄3 in (1.7 cm) wide to create holes about 1⁄2 in (1.3 cm) deep. Set 2 1⁄2 in (1.3 cm) screws in each bracket. Use an electric screwdriver to secure the frame to the cabinet. Then, set another screw in the front end of the bracket to secure the slide in place. Gently install the screws and avoid making them too tight. Line the drawer’s slide rails up with the cabinet’s rail frames. The drawer’s slides should fit in the frames. Push the drawer in to make sure it glides smoothly. If the pieces are installed correctly, the drawer will come to a gentle stop inside the cabinet. If something seems off, check to make sure the slides are even and level. You may need to readjust the screws.
Set the back brackets in the slide frame. Align the slide frames with the bottom of the cabinet. Use a level to straighten the frames. Mark the position of the frames with a pencil. Predrill holes into the wood. Screw the frame pieces in place. Fit the drawer into the cabinet’s slide frames.