I'll give you a few links to look through for getting ideas. Basically you have a drainage layer on the bottom made of Hydroballs (clay balls) or a false bottom madke from eggcrate. Then some screen material (window screen or substrate screen from the pet stores). Then a layer of Eco Earth or Plantation Soil (available thru pet stores). Some members use a layer of sphagnum moss below the top soil layer to retain more moisture but I haven't used or needed it in my dart vivs.

Here are those links:
http://www.frogforum.net/vivarium-te...pic-heavy.html

http://www.frogforum.net/vivarium-te...se-bottom.html

http://www.frogforum.net/vivarium-te...d-journal.html

http://www.frogforum.net/vivarium-te...cal-build.html


Hope this helps