Mark, really easy, i just used satin black smooth hamerite, just ruff up the surface with a scotch pad, clean them down with pannel wipe, and spray, do thin layers and alow to dry, hamerite can be a pain if you dont let it cure, i left mine in the airing cubord for a few days, just take your time and not to much paint and let it dry well, they are my top tips,
no primer needed as that stuff goes strait on metal,
hope that helps.
BLACK is the new BLING