I have an idea for a product which I want to be made of plastic. I am not a designer, engineer or manufacturer so I am not sure how to go about the process.

I am looking for resources on how to design my idea and submit it to a plastics manufacturer so I can create a prototype of it. Then make corrections etc. until I have a functional product.

Can you tell we where to begin and what the process is? How can I find these resources to design and build my idea? What is are the correct terms for product designers and companies that create plastic products?

You help is very appreciated.
Regards,
Mihir Shah