Make sure back of cubby hole is clean for good adhesion
Test-fit your Extender before removing tape backing
Remove paper backing from double-sided tape
With palm down, press down on inside middle of Extender while sliding it to the back until it makes contact. (Image 1)
With palm up, use fingers to firmly press along the entire back of Extender to ensure good strong adhesion at every point. (Image 2)
Note: The Extender is two pieces locked together with friction. Applying too much force may dislodge them. Pressing it together firmly on the left and right corners and in the center will snap them back into place. Optionally, you can use an epoxy glue to seal them together.