To use the online ability of the TV, you need to specify files for it to grab.
It does not have API support, which makes YouTube video playback impossible.
Instead, you need to provide a link to the file you want to play, as in, it needs to contain something like "example.mp4".
You can also use the offline capability by placing mp4 files inside the tv folder at AppData\Local\VotV\assets\tv.
If you do want to use YouTube videos, you can do it this way using a video downloader like yt-dlp ( a free open-source cmd downloader you can specify to drop downloaded videos to that folder.)