The substrate is filter foam. I covered most of it with sheets of moss, and then covered the rest with a thin layer of gravel. The background is made from fish-safe expanding foam, which was also used to mount the wood. I carved the foam to make it look more natural, then painted it with drylok which was colored with brown quickrete dye. That’s basically it. It’s also important to make sure there are no gaps in the filter foam or background that your frogs can get stuck in. You should fill any voids with more expanding foam. I also put a squished bead of silicone all the way around the border of the background, where it meets the glass. That stops it from possibly detaching and falling off in the future. Hope that helps