Dangit. Ok...let me try again. Take your stock rectangular tank. Say you're looking at the tank from the front. The ledge will be on the right, and the drop will be on the left. Add the vertical piece for the drop. Add the horizontal piece for the ledge, install it on top of the vertical piece running towards the right. Cut it 6" short so that there is a 6" gap between the ledge and the right pane of glass on the aquarium. Now make another vertical piece that sits on top of the right end of the ledge and goes to the surface of the water or top of the glass aquarium. If you wanted (just for example) you could pour sand in the open part on the right side that would go down under the ledge.
It's like building a set of stairs...if you know the lingo for that. You would be installing TWO rises, and ONE run within the stock aquarium. The second run (the top one) would be left open, and would be at the tank's surface.
That help at all??
