I have what is probably a silly question. When you have an idea or something you want to mass-produce, what do you actually do? Is there some website that you can upload your design to, then receive quotes from factories that agree to manufacture N units at M dollars/unit? Or do you usually go through an agent?

Sorry if that seems dumb. I just have literally no experience in this area; if someone handed me a design and said "Manufacture 1,000 of these" I'd just stand around dumbfounded.