Pile up the substrate in the one corner and than dig a peice of wood in a little. To creat substrate around the wood. Than try to put the other wood on top. Put a amazon and a few java ferns under the top one and around the bottom wood in the substrate. Low light stuff because they will eventually be shaded. But java I don't think are too picky which is great.
Lead off around wood and down the slope with rocks and edge the rocks with HC or a low cover plant. It would cap it off and make it look random yet scaped.
On the other side jeep things low with micro swords and low lush plants. And if you want place more rocks scattered around for the ground cover to wrap around it.
Rocks are in almost any natural environment and IMO belong in a tank. Look for petrified wood. Rear colours and shapes. Can also be broken up and used to accomplish different sizes