The Production Plan sets out the individual steps required to manufacture a finished product. It is a detailed document that provides step by step instructions including the materials to be used, measurements to be marked out, and the tools, equipment and manufacturing processes that need to be used.
To be effective, production plans need to clearly explain each step with detail. They must be methodical to the point where even a person who has not been a part of the design process or knows the product can manufacture the finish product. It is, in a way, no different to writing a recipe for instructing someone how to mix and bake a cake.