I keep it simple myself. You could set it up like a fish tank with fine gravel as a substrate (well below the water line), plant it with plants that will emerge above that water line or floating plants like water lettuce, and provide platforms on which the toads can crawl up on. Drift wood, whether artificial or real, works well for this. You will have to feed them in another enclosure, such as a Rubbermaid box, as crickets drown so easily.