If you'd asked this in your first post, it'd have been better understood....I think. Anyways, post #9 & 10 have the correct answer.
Its not rocket science. Mount the red dot, go to the range, run the target out 15 feet and fire a round or two...make any adjustments and repeat. after a few rounds, you can run the target out to 50' or so and finish your zeroing.
As for where to zero or place the dot...on the front sight dot or above, that's personal preference.....which ever you prefer.
I DO have a tall front sight mounted on a couple of my pistols. The tall sight, in the beginning helped me find the dot. Now, I rarely even notice the front sight, as I've gotten used to proper hold, etc. ... when I pull the gun up to look thru the optic....there's the dot.
To answer your question, when I'm looking thru the optic, the red dot is above the front sight.
Or when I'm looking thru the windscreen I sometimes see this. Yes, my grandson wanted to go for a plane ride the other day. I took him on short hop around the pattern.