if your at bere metal now you will need to metal condition the metal first then hammer and dolly all your highs and lows or metal file your dents then use an epoxy primer then what i use is a high build primer it sprays on really thick so it levels out really good but when you get you panels straight then shoot your primer surficer on because that hibuild will recoat react with your paint. Start with 80 then 180 then 220 then 320 400 500 600 never go more than 100 each time you sand. let me know if you need any thing else and let us know how it turned out
