Our bio active setup has a two inch layer of ZooMed clay balls on the bottom, then a screen for the substrate barrier, then 16 quarts of Josh's Frogs ABG mix (roughly 3 inch layer), then sphagnum moss mixed in and on top, and then leaf litter, which I collected maple and oak leaves in the woods (no chemicals sprayed on) and boiled them to sterilize. We also found a log and baked it.
For plants we used Queen Marble Pothos and Spider plants. Josh's frogs website has a whole list of plants that are good to use with ball pythons. We also rinsed everything with water to make sure it was clean and to reduce dust.
Lastly we added about 100 isopods and springtails. Was told that if they are low on food to just drop in a few kibbles of dog food.