How to setup Plex to STB

Hello, i plan to install Plex Media Server to my server, i looking information how to setup STB box like in the attached picture, pay tV from Telco, do i have to use TV tuner? what TV tuner reccomended

Plex Consists of a server and a client.
The client can be a multitude of boxes!
Roku
Shield TV
Xbox
Almost anything that runs Android
Fire TV
Apple TV4
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We don’t have a Plex client for that. If it supports DLNA, you could turn on Plex’s DLNA server and access it that way.