Welcome aboard.

I would cover your supstrate with leaf litter, which you can get from either Black Jungle (blackjungle.com) or Josh's Frogs (joshsfrogs.com). The leaves they carry do not break down so quickly and are nontoxic. The leaf litter will look nice, keep substrate from sticking to your frogs, provide hiding places for both frog and prey items, and keep your frog from tracking substrate into the water bowl.

Also, your sphagnum is very much dead. It's not going to grow. Sorry.