I have a modified product and, I am interested in manufacturing/marketing it. How do I go about doing it?

Answer 1

find out a company which is willing to manufacture it for you. but be ware of the copyrights and patents etc.

Answer 2

First, if you have modified a product that is already on the market, and not being a represenitve of that company.
You may very well be in violation of copyrighted or trademark infringment.
This could be very bad.
I suggest you do a little more research on your project, it may save you a lot of time and headaches down the road.
Don