If I use the waxless by Fluidmaster, I push it on the bottom of the bowl.
Sometimes if the flange is low, it can be a good way to go.
Doing it that way, it seems to work.
If I use wax, I set it on the flange.
This works too.
If the flange is higher than the finished flooring, then a single wax on the closet flange works.
If the flange is lower than the finished flooring, I stack two wax rings. A regular wax down first, and then a wax with horn over that. The toilet then sets down over that and compresses the wax.
Note: I always check to see if the bowl needs shimming before I put the wax down. I set the bowl down and see if it rocks. If it does rock, I might place two shims at the back, pinning the front of the bowl down to the floor. I then lift up the bowl, drop the wax(s) down, and then set the bowl down again.,
Since this flange was above the flooring, one wax ring worked.