There are expert/professional painters here, but I am a novice and an amature hobbiest.
What works for me is a chemically stripped frame. I hand sand with 80 grit. Or however else you want to get the frame bare. Smart people sand blast it, but I have more time than money.
I use rattle can etching primer on the bare metal. I do not go thick, not at all, not if you're big, not if you're tall, not even in the Fall. However if your weather is humid, rainy, etc, or you will not paint within the next day or so, go heavier to prevent rust.
Scuff or wet sand the etching prior to prime. Use a rattle can gray sealer, or with your new out fit, a 2K (two part) kit. It's best, and you can color coordinate the base coat to deal with the coverage of your top coat.
Things dry super duper fast here in the desert. Most everyone has to wait 24 hours, or even longer. Cold and damp is your enemy.
When you use two part paint, do not let the stuff setup in your gun. Don't freak on primer for mini bikes. Seriously rattle can is fine. If you start using expensive paints however, you will want the security that 2K primer brings.
Everyone has their own way of doing things, so what I am saying is not the bible. Weather and technique and prepping have more to do with the paint job than anything else. Oh....add drops of forehead sweat into paint as a possible way to add special effects.
And stay away from Nason reds, unless you need crappy coverage. Stay away from all reds if you can help it. $$$$$$