how to prep new fender

[mikeguy]

i got a new front fender from classic parts for my 1963 k-10 stepside. it has the black primer coat on it.i have the truck primed in epoxy primer with the catylist additive. i'm not real sure what to do with the new fender DA with 80 grit and shoot with the same primer as the rest of the truck or go right to high build primer. i havent done this stuff for thirty years and all the new technology makes my head spin.