Instructions

Copy the link in the address bar including the room number to someone so they can join the room.

There are 3 possible video source methods that can be used:

YouTube

Enter a youtube url into the input bar, and press enter or click the stream button.

Direct links to video files

Enter a url of a video stored on an http server publicly, such as https://example.com/video.webm
In this case the file needs to be encoded with a format supported by the browser. For example, h.264 video and aac audio standards. They also need to be http streamable, i.e., encoded with -movflags +faststart. Note that a webpage which has a video on it isn't necessarily the link to that video.