Here's an example of someone setting up a vivarium/terrarium with a false bottom.
http://badmanstropicalfish.com/vivarium/vivarium.htm
It doesn't have to be that complicated or that difficult. My false bottom consists of one sheet of eggshell plastic covering 3/4 of the tank. It's covered with a sheet of mesh screen and supported by rocks (though PVC pipe from Home Depot works fine also). Put pebbles or clay pellets on top of the screen, then soil (mostly ground bark), then moss or wood chips. It took me an hour to do it and it's simple. Mine has a filter in the water and an undertank heater that keeps the humidity around 90%. Filter isn't necessary but you don't have to change water so frequently with it.
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Kane