Measure the distance from the ends to the screw holes on the keyboard slide using a ruler. Each slide should have two holes, one near each end.
Mark the underside of the glass desk with a permanent marker using the measurements taken from the slides. Use a ruler to guarantee a straight alignment of the marks.
Rip eight thin strips of masking tape from the masking tape roll.
Place an X made of masking tape over each mark on the underside of the glass desk. Redraw the X with permanent marker on the center of the masking tape X.
Drill a 1/8-inch hole into the center of each masking tape X using a 1/8-inch diamond tip drill bit and a cordless drill.
Remove the strips of tape.
Attach the keyboard slides to the underside of the glass desk using the screws included in the keyboard slide package or 1/2-inch long glass screws. Align the holes in the slides with the holes in the glass and use a cordless drill to insert the screws.