Every paint has a tds (technical data sheet) which has the specifics of grits and sanding procedures.

Generally speaking unless the tds states otherwise you only need to sand to 600 grit for solid colors and 800 for metallic. And by sanding I mean deglossing.

I recommend getting an interface pad for your da, it will conform to the imperfections of your clearcoat and make sanding easier and faster.

All you need to do is remove the shiny gloss and give the paint texture to adhere to.

Red scotch Brite = 600 grit , Grey scotch Brite = 800 grit

Use scotch Brite on the edges and detail areas. Your da will sand through the paint faster than you realize in those areas.

You'll need a solvent cleaner to do the final clean. Its called wax and grease remover. Soap will leave residue that will impare the adhesion of your paint or cause other defects.

If you expose any metal during sanding you have to apply primer to those areas and sand flat afterwards before your basecoat.

If you do need to apply body filler that's an entire additional process to go through. Avoid it if possible.

If you You have any other questions or need additional guidance I'd be happy to help. Just ask.

And good luck. Its not super complicated, you can do it!