I have a cermaic tile floor going in. does the tiolet flange need to be flush with the tile or can it sit on to of the tile.. I planned on it sitting on top, but I seen else where when they have been installed sitting flush with the floor. Which way is correct?

This should help, its an offset but the install is the same, on top of the floor. Installing An Offset Toilet Flange - Drain Plumbing, Soil Pipe

A toilet flang should be 1/4 inch above any flooring, that's the correct way!