A false bottom is good for your frogs if you want to have live plants, and don't want to spend as much time cleaning the tank on a regular basis. What you're doing is raising the land level a few inches so that the bottom is all water. This makes it easier for you to have a filter cleaning out all the water, and also easier to create a waterfall and pond area. It takes a bit more time but is well worth it in the end since all you have to do to clean the tank is wipe down the sides with vinegar and water. I have added a website that I used and is really good at explaining the steps. Hope this helps!

Link