It would be nice if you could create your own working prototype.  Hopefully you can.  I started my prototype with cardboard and paints.  I cut it to the size I envisioned and painted the design on the pockets.  I know it seems elementary but it enabled me to make changes before we began sewing.  I had my mother sew the first bag which ended up being more difficult than we expected.  This will give you an idea of the time that goes into a finished product.

Remember, you don’t have to worry about color choices and materials at this stage. You will get a better feel for this once you begin to see price quotes.  The purpose is to have a working prototype that you can present to a manufacturer.  They will give you options at this point.  Remind them that you have a provisional patent (patent in process) and have them sign a non disclosure stating that they won’t reproduce the product. It’s just extra protection.

I wanted to keep the manufacturing in the US so this is where I began.  It is easier to find manufacturers in your area and makes it convenient to make changes.  If you decide to go oversees, at least you now have some experience.