Here we call it a clear coat system where you have primer, base coat, and then top clear coat.
You can do spot repairs just got feather the edges to blend the paint. The amount prep and other work needed depends how much damage that is got to be repaired.
If unsure about how to go about it get yourself a test piece to learn on first. That way if you mess up it is no big deal as you are learning from your mistakes. (I hope) Even the big auto company screw up at times painting cars with this system.
