Wow, I don't know where to start. Scotchbrite pads and your arms and elbows should get the surface rust off. If it's worse than that...???
Light coat of primer out of a spray can would be better than nothing to keep it from rusting again.

I'd pressure wash the engine compartment and maybe the trunk and blow dry. Then paint over it, Unless your gonna do the car right and media blast the whole thing.
Good luck and read some of the old threads on this site. Plenty of good info on how to restore cars.