You're kinda going about it backwards.
You see the big companies that are already involved in this business hire small armies of people to develop ideas, product, methods, packaging, manufacturing, marketing, sales and probably about a dozen other things that I missed.
Coming in and trying to compete with them is incredibly hard - it's kinda like saying how do I setup and open a 3 Michelin star restaurant and what should I pay the Chef?
It's not really going to ever work.
That said - there are many who have found a niche and then leveraged it into their dream. Almost universally they are people who had an idea, chased it and developed it and then ended up selling it.
Like everything great and grand it always starts small - local sales to private shops, then sales to specific areas/communities, then sales to territories, then regional sales, then the big daddy of National sales. Some continue on to the international scene.
The frozen food market is not a niche looking for someone to fill... it is heavily saturated. You need to have an idea to bust into that market - something that sets your product apart, something that makes it different and then you need to develop it.
Then you have to fight to make sure the big corporations don't just copy and crush you - this is usually a marketing function.
Anyway probably not what you want to hear but it's worth what you paid for it.