The username is usually displayed in the URL in your address bar. For example, if the URL is
https://www.twitch.tv/shroud, the username is
You can find the video URL or channel name to add to Multiwatch. The video URL is structured like this:
https://www.youtube.com/watch?v=mTH8yPp1Fr4. The video ID for this stream is
To share your Multiwatch with friends, copy the link in the address bar and send it to them. When they open the link, they will see the same stream structure as you.