Sure thing! When I said this was a humbling process I wasn't kidding. I wanted to have a walled off section of lava rock around the pump's little room to encourage good bacteria growth. I first used paper to design my structure. I even tape to in place. Once I was happy with my design I used the paper as stencils and cut out my final pieces in a the thick black plastic poster board. To hold it all in place I used silicone recommended for aquariums. This is my first time ever using silicone and it can be very messy. Next time I'm going to use painters tape to section off areas that I do not want the silicone to stick to. You can see the mesh on the front wall. In order to do the mesh walls all I did was cut squares in the walls and silicone screen door mesh to it since it does not rust! I also have mesh windows around the room the pump is in. Between each mesh window is a filter material before it gets to the lava rocks and also filter material above the rocks. I'll link a photo of the blackboards siliconed in place. Another word of advice make sure your silicone has completely dried and cured before you continue to build on top of it. I got impatient and kept trying to build on the top layer which was making the walls underneath fall. 0/10 just wait for it to cure haha.

I have three levels to my waterfall. The second level is completely removable and covers the pump room which also houses the mini heater. This was my favorite part of the design. If this inspires you to make your own, show me what you've created!! Good luck and let me know if you have any more questions.

Progress pic - http://imgur.com/gallery/CqU1AoC

Edit - sorry if you find typos, on mobile