You can't.  The Sonos devices that support a TV source connect via HDMI-ARC/eARC.

Older Sonos PLAYBARs and PLAYBASEs, no longer in production, use an optical connection. 

If you have an Apple TV hooked up to your tv and a Sonos Beam/Arc you can Airplay the tv sound to it by choosing temporary sound. I have been having to do this for the past few days as I accidentally popped the tv’s hdmi arc outlet into the tv trying to replug it in.