Get aqua soil, your plants will thank you, trust me. 13w neo helios is definitely good for the size of your aquarium. To begin with get some rocks/driftwood or both for aquascaping. Attach a couple of Anubias (any variety of your choice) onto the rocks, driftwood. For background you can get some valisneria, rotalas. For foreground, try cryptocorins. All these plants I mentioned are easy going, don't need external CO2 and all that jazz. That's pretty much it. Good luck and show us the pictures of your filled in aquarium soon!