ahhhhhhh ok I can help you. I think I know exactly what your attempting to use. lolIts the clamp itself. It was a cheap thing that applies using a sticky pad and it of course won't stick. Keeps falling off. The dome wants to turn crooked on it also when its hanging. It was a petsmart special I grabbed one day. The regular ones were out of stock. Only ones I found that clamped to the table were only 36 inches tall and the cage being 36 tall it wasn't gonna work.
Did you buy this? https://www.amazon.com/gp/product/B007D1BUJY/ref=ppx_yo_dt_b_asin_title_o04_s05?ie=UTF8&psc=1
If so you have to drill holes in that mounting plate that line up with your cage frame and then use quarter inch self tapping screws to mount it directly to the frame.
See my pics. I secured my clamp lamp with a zip tie to get the exact angle I wanted.