Wipe down the shelf you are connecting it to with a clean, dry cloth. Squeeze (pinch) the suction cups to make sure they make a U shape instead of being flat (this helps the suction). Ensure all three suction cups are installed, then firmly press the organiser up against the underside of the shelf so the suction cups grip. Hold for 10 seconds and release. With a little bit of pressure, try to pull the organiser down to check if it holds. If it doesn’t, you may need to place the suction cups in hot water for 30 seconds (this “resets” the shape of the cup for better suction). Once the cups are gripping, they hold firmly.