In the Amazon Alexa App you can set the Fire TV built-in Alexa component to use a sonos speaker as default, but note this is for Alexa responses, not for the Firestick App audio output, which will still output to the TV speakers, or the TV’s connected Receiver, like the Sonos Beam, Arc etc.
NB: You can ask Alexa to play music audio to your Sonos devices (also using the Alexa component). With some configuration in the Alexa App, Alexa can even auto-group/ungroup speakers using playback voice instructions. (Search for Amazon Alexa Groups in this community for more information).
The table below is quick summary/example of some of the voice commands you can use with the FireTV or via linked Sonos Alexa device (Not an exhaustive list) just to help get you started with Fire TV
| Go to Fire TV | Alexa, watch Fire TV |
| Play a movie or TV show | Alexa, watch The Grand Tour Alexa, play Stranger Things on Netflix Alexa, play comedy on Netflix |
| Search for movies and TV shows | Alexa, search for [movie / TV show] on [app] Alexa, find [title / genre] on [app] Alexa, show me [movies / TV shows] on [app] Alexa, find [actor] movies on [app] |
| Control playback | Alexa, play Alexa, pause Alexa, stop Alexa, resume Alexa, rewind [timeframe] Alexa, fast-forward [timeframe] Alexa, go back [timeframe] Alexa, jump forward [timeframe] Alexa, next / next episode Alexa, watch from the beginning |