Listening to A2D2 Stream with your Sonos system is really easy. 

Just connect to the A2D2 Stream interface, if you've kept the default settings, you'll find it here: http://a2d2.local

If A2D2 Stream detects a Sonos system on its network, then it'll list the available speakers and groups. Just choose the speaker in the list you'd like to hear A2D2 Stream on and it'll do the rest for you. 

You can play/stop A2D2 Stream on multiple speakers and groups, and once playing you can also use the Sonos App to switch speakers.