Hi, I would recommend to start from reading this article about smart tv app development https://opengeekslab.com/blog/smart-tv-application-development just to be on the safe side and get an idea about such development in general. You see, they are real professionals with a huge experience and dozens of great products. I would advise to start from reading their reviews and checking their portfolio. Simply give them a try and Im pretty sure you`ll be satisfied. Good luck
Here are some basic recommendations and tips:
Check experience. You wouldn’t want a doctor, fresh out of university, with no experience yet to conduct your knee surgery. Same with your business – if you hire someone, better hire a developer who knows his stuff. It does not necessarily need to be a top-expert, though should be able to provide the portfolio of past works. You can even ask for samples of his/her code. Build relationship and communication. Seek someone reliable, seek a developer interested in your business and outcome of your common work, not just in development. Sounds all cliche, but it is so. You’ll have to get along, to build a relationship with to get your app going. Language or cultural barriers, for example, or many other things may get in the way.