It's not very difficult, grab yourself a couple cultures of springtails or isopods or both. Since your reptiles won't eat them, you can toss them in, they will reproduce in your viv. In a month or two you'll see them everywhere along to substrate. That was why i said it depends on animals. If you were going to house dart frogs, i would have recommended introducing the microfauna for at least a month before adding frogs.
As for links, there a lot of threads about microfauna on dendroboard and frogforum