When deciding to get an invention designed and manufactured you will typically need to liaise with a number of suppliers or contractors that are going to help you with the stages of the product. To control your project effectively you need to meet with al suppliers and understand their lead-times (time to complete) and their resources (how many people are going to work on the project).
You may find that most of the time you feel helpless while all your suppliers are doing their thing to bring your project to life. You need to be in constant contact with your suppliers ensuring you understand every stage they are at and if they are on target. If your supplier is not on target then you need to understand why, what problems are they having and if they can fix the problems. You need to inform the next supplier that follows if they will be delayed.
Please be aware that some companies designate time slots to do your work. These time slots are allocated based on your predicted dates. If your dates change you need to see if your slots can change too or if you have to wait for them to do finish other jobs first.
I have project managed hundreds of jobs ranging from small products to 40 tonne machines for the mining industry and every job is completely different. The things that are similar is that they both need material and both need resources. To control your project involves taking these two factors and assigning then to your suppliers.
My advice to you is to start working on your Project Management skills ensuring you can control your project with ease.