so i would like to ask: basically what do we need to prepare to get the best spray-painting experience and achieve the best results?

i know that we need sand paper, but how many do we need? there's a few type as well: 200, 300...

of course besides that, we need the colour spray paint of our choice, other than that i've been getting many versions of spray painting techniques like you need a primer or undercoat and a finishing coat as well for optimum painting results...

so sifus here may explain to me more?