The Sling TV app is not pre-loaded on the DVR+, but is available.
To see how to install Sling TV onto your Stream+, you can find instructions at the Sling TV Help Center.
Please note; ‘Live Channels’ is a Google implementation, in collaboration with Channel Master. Channel Master is not responsible for ‘Live Channels’ functions or issues. All Guide data, logos, and images are provided by Google. Any Guide data issues & questions, and bugs should be reported to Google Support.