See the section on similar threads listed at the bottom of this page.

The one titled A Quick False Bottom does have pictures.


I false bottom allows excess water from misting to drian off and not rot or saturate the substrate but needs a way for you to remove the excess when full. It also is used to hold the reserve water from a water feature.
If you have live plants then yes, it would be advisable to add in a false bottom. This way your plants roots do not rot and the water is filtered as it drops through the substrate.