Unfortunately I also don’t have any experience with video streaming to the LW frontend and don’t remember which protocolls are supported (like rtsp, rtmp, http). The link I posted was the first I found for setting up video streaming on the raspi, but it is not related to LW. The username & password is optional in a streaming url and so is the endpoint (the part after the IP:Port). They are dependent on the configuration of the streraming server. The url example I have posted is from a surveillance cam.
Hint: The streaming url is not the same like the url of the streaming server website. If you call the url with a web browser and get a page with an embedded video player, then it is the url that the videoplayer uses that we need.
I also couldn’t find any documentation on the LW video feature, but I remember that @Jorge_Robles has implemented that part. Eventually he can help.