Google Home voice commands always start with “OK Google” or “Hey Google”. You can then tell Google Home what you'd like it do. 

For example:

• “Hey Google, what's playing on CBS?”
• “Hey Google, watch [CBS show name] from CBS on [Chromecast Name]." 
• "Hey Google, pause on Chromecast XYZ."
• (While paused) "Hey Google , resume on Chromecast XYZ."
• (While a show is streaming) “Hey Google, next” - play next episode available in that series
• “Hey Google, turn on closed captions." 

Happy streaming!