In order to access your files from your MacBook Pro, you need to follow the instructions here. 

Sonos has recently changed the way that their new app accesses audio from shared libraries on the local network. The previous S2 App supported SMBv1 and HTTP protocols for file sharing, but these have known vulnerabilities and are no longer used by Microsoft, Google, Apple, Amazon etc. and all has now shifted to using SMBv2 (or higher) file sharing.  You may need to upgrade your shares… see these links depending on how you share your library tracks…

For MacOS users, see this thread.

In order to play your library from an iOS device, you have to have a Sonos device that accepts AirPlay 2, and use that to connect, using the Apple Music (or other) player on your iOS device. 

Thanks, that worked from my phone. Can’t get to play from iPad, but I’ll keep trying. 

If you’re using AirPlay 2 from the iPad, I’ve had a few (3? 5? Been a while) instances where AirPlay 2 would fail to send a signal. My initial reaction was to blame the Sonos, but eventually found that a power cycle (of either the iPad, or the iPhone) fixed the issue. That’s after a lot of chasing around, rebooting the Sonos speakers and my router. Turned out (and oddly, IMHO) to be the Apple device.