I'm Sr. Consultant Development, have experience in streaming for IPTV(Roku, Amazon Fire TV, Android TV), mobile(Android & iOS) and web application. I'm also experienced while developing API which is used in Roku channel, Amazon Fire TV, mobile, etc. Message me if you want to know more about me or my work.
Here are few things which are required to start Amazon Fire TV channel
(1) A video hosting server if you are providing VOD(Video on demand) like movies, episode, etc.
(2) A web application that will provide you to upload/ delete video, audio, user, etc
(3) An Api or web services which is required to communicate between video hosting server and Roku channel
(4) A Roku application that is called Roku channel
You didn't provide detail of your requirement. I'm offering you roughly cost and time for AMazon Fire TV App and I'll update cost and time after discuss with you.
Previously I was working for company, now I have started working as freelancer.