Do I need to apply clear coat over the carbon fiber?

Yes. Clear coat protects the carbon weave from UV damage and yellowing. Sand the surface and prep it before applying your chosen automotive clear coat system to preserve the finish long-term.

Should I seal the edges where the panel meets the body?

Sealing the edges is recommended to prevent moisture intrusion and keep debris out of the gap. Use a flexible, paintable sealant along the perimeter after installation and your topcoat is cured.

How do I prep this for paint or clear coat?

Sand the surface lightly with appropriate grit to scuff the weave, then wipe clean. This gives your finish a better base to grip. The panel arrives unfinished, so all prep and topcoat application is your responsibility.