Hi there!
I just started with dart frogs myself, and have been having so much fun with them!
At first, I was confused about the false bottom thing too, and it seemed like a tough project. But it really isn't hard at all.
I have pictures of my 10 gallon vivarium here:
photobucket.com/albums/v630/vamppire/Leucomelas Dart Frogs - Brad and Janet/
10 gallons is good for a pair of darts. I have 2 leucomelas frogs, myself. ^_^
The false bottom technical aspects are pretty basic - you raise the substrate, so the water can drain to the bottom so the substrate is not constantly soggy and sitting in old water.
To do this, you need something to hold up the new floor - most people use PVC pipe connectors. I used 6 2" connectors for my tank. Look in the plumbing department of your home improvement store. (Do you have Home Depot or Lowes?)
The floor itself is made using what's called "egg crate." Egg crate is actually a light diffuser used for fluorescent lights, so you can find it in the lighting area. You cut the egg crate with a cutting tool (wire cutters work) so it can cover the size of the aquarium.
On top of the eggcrate, secure some fiberglass mesh (not metal). This keeps the substrate from falling to the water. I used 2 layers of mesh, and probably should've used at least one more, as some dirt escaped to the bottom. I found the roll of mesh in the door/window section of my store.
I used a Repti-flo 250 pump from petland, with 1/2" hose (also found in the home store - petland doesn't have it). Some people house the pumps in containers under the water to help keep dirt out to prevent the pump from clogging, but I didn't do this. I cut a removable square out of the eggcrate (left the piece there, but it is disconnected from the rest of the crate), so if i need to remove the pump, I only have to dig up one corner of the tank to get it, and not the whole thing.
That's basically all there is to the mechanics of the false bottom system. Just have the hose come up from the crate, and the rest is all aesthetics and fun! I have my water trickling down some rocks, as that is really all I could do with my supplies and the room in the tank, but if you are using a large tank, more elaborate waterfalls are a possibility!
For the substrate, you want to have a drainage layer on the bottom. I used the clay pellets from blackjungle.com (most of my vivarium items came from them), covered that with sphagnum moss, then used the coco fiber brick stuff. I covered it with live moss. I used blackjungle's tree fern background and their ghost wood (which is supposedly good for humid enclosures). Their jungle pods are really need too!
Unforutnately, I ordered 4 plants from them, and the fern is the only thing that survived. For their price, most were quite small and I am disappointed they didn't last. I assumed that since they only really deal with dart frogs and vivariums, that the plants would thrive in one. So I would recommend getting your plants from the home improvement store if they have a garden center.
Anyway, I hope some of this was of help. 
Don't be intimidated by the false bottom setup, it is easy and you will have tons of fun setting up the water features and the rest of the decor! (and some frustration, but its worth it in the end!)
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~ Vamppire
Queens, New York City
