Beginner, help with scratch

Hello all,
Looking for some help,fixing a scratch on a metallic gray Acura TL. I am new to scratch repair, and would really appreciate some specific directions and what materials to use. The scratch is about 5 inches long. You can catch your fingernail on about 80% of the length of the scratch, but it’s not too deep. I bought a touch up kit that came with matching paint, a tiny brush, filler and leveling solvent. I filled the scratch, leveled and used the brush to dab in the paint as directed. Paint matched well, but you can still see where the scratch was, and it is not smooth.

I am assuming I now need to do wet sanding and then polishing. I don’t have experience wet sanding. I would really appreciate some direction from here and what materials to use. Also, where can I get the proper grit sandpaper. I do have a DA polisher, cutting and polishing pads and polish.

Thank you so much for the help!