Kinfing putty help

[millzy]

Hi Guys

Looking for some advice, I scratched my car years ago when I first bought it and its about time I sorted it out.

I have prepped the scratch and applied Knifing Putty , before I apply the primer what grade wet and dry should I use on the putty? And is the and tips or tricks to sanding the putty down with out causing sand paper scratches to the surrounding paint?

Any advice will be gratefully received