Ways to display information on a TV or how to make an information board?

Question

Video broadcast

Hello!
I don’t know why I can’t find the information I need, apparently I’m not strong in this area at all.
To business. Tasks:
1. At least - display the schedule on the TV screen (there is SmartTV, there is no VGA connector).
The timing is limited, so I planned a temporary solution - connect the thin client to the TV using a vga cable (an unusual straight cable, and through vga adapters - rj45 (8p8c) + twisted pair connecting them). But I got screwed on the TV, there was no vga connector, well, that's it, I thought it was in all modern TV sets ...
Now the question is, how can I use smart?
Download a browser extension for viewing ppt files and open a presentation from a flash drive in it? Or is it possible to open the file from somewhere on the network?
Overtake the ppt format schedule file into an html table and specify the network path to it in the browser? Then the question is about html)))) how to overtake beautifully, what was stretched to full screen without losing proportions?
Convert the schedule file in powerpoint to video and broadcast it from a flash drive? How then to loop?
And most importantly, how to safely set up smart if I pull the schedule from the site. Those. how to block access to the Internet so that he does not update anything, etc. Did you only have access to one page?
2. Maximum - display different types of content on several TVs, but manage from one place.
Let's say there are only 5 TVs, 2 show the schedule, 3 show the video. And not all of them are smart and there is no LAN connector.
I know about the length, but is it possible to display the schedule through it? I read about raspberry pi, but did not understand the essence of how it works, just a board instead of a thin client? How is the image displayed over coaxial cable in stores and TV advertising?
Also, the whole thing should turn on and off on a timer.
I would be very grateful not only for direct answers to questions, but also for links to detailed articles that describe the general principles of such systems. I will also be glad to have good articles on the construction of information systems with such equipment (displays, infomats, telephony, etc.) I am interested in the organization of routing and access restrictions, information security in general.
Thank you all in advance for your replies!

Answer 1

We put an application for presentations or whatever needs to be driven there.
If for the video stream - VLC player.
Of these, we open the desired file over the network ... Either
loop the video, install VLC, load it into the internal memory of the TV set, start it with repetition
option, we install Linux on a PC, we also drive the stream through the VLC player, from the console. And at the same time we get full remote access to the piece of iron using, for example, VNC.