On your Mac or PC, make sure you are running the latest version of Chrome (by going to chrome://settings/help) then start the video player from your My Library page by clicking WATCH NOW.
Once the video is playing, as soon as possible, click the casting button
in the bottom right corner of the video player, then choose your Chromecast device from the pop-up menu.
On Android or iOS use the nugs mobile app and access your Livestreams from the My Library> My Events section of the app. Click the casting button in the bottom left corner of the video and choose your Chromecast device to start casting.