Don't try to paint plastic. If it is metal get some blue tap and put it on everything you don't want to paint. Sand finish off the existing with some 200 grit paper or foam sanding block. Get some spray primer , don't over do it with the primer. Paint let dry, then clear coat, wait a couple of day. It will cost you over $20 for the supplies if do don't already have it. When you are done with the spray paint turn it upside down and spay until just air comes out. Any type of handy person will have some spray primer, clear coat will be harder, ask a car guy.