Product Idea

I have a product idea, but I don't know where to start, and I don't have a lot of extra money. When I google "how to create a new product" I get all these articles from companies trying to sell their manufacturing services. Is there a guide or step by step book that outlines the process without trying to sell me something? Or is a manufacturing company actually worth it in the end? Should I consider asking for investors? When should I purchase a patent? Really just looking for the best way to start and/or any guides that are not advertisements.