Open the cabinet door. Place the soft-close piston attachment in the upper corner of the cabinet opening on the hinge side. Point the cushioned end of the piston toward the front edge or the cabinet door. The adjustment screw on the back of the piston points toward the back of the cabinet. The attachment is designed so its housing seats into the corner of the cabinet opening.
Hold the attachment in place firmly with one hand. Drill a pilot hole through the screw hole in the attachment housing. Each attachment brand differs, but the bit you need is generally around a 3/32 size.
Screw the attachment to the cabinet housing using the pilot hole and the supplied screw.
Close the cabinet door. If there is a gap between the door and the housing, open the door again and turn the adjustment screw on the back of the attachment a half turn counterclockwise. Test the door again. If it still does not close all the way, turn the adjustment screw another half turn. Continue this procedure until the door closes with no gap.