Output Apple TV to Sonos 1

I purchase a Sonos 1 speaker and am trying to connect it to Apple TV.

I have updated the SW on the speaker and the Sonos app.

I have added the Sonos speaker to my Home app.

I can use Airplay on my phone to select either Apple TV or Sonos speaker and use my phone to play through either.

However, when I select Airplay (selecting while in Apple music or through long push of TV on remote) the Sonos speaker is not an option.

How do I get Apple TV to 'find', 'discover', 'connect' to the Sonos speaker?

Everything I read is about adding it to home app, playing via phone, etc. Thanks