You will need to use a Sonos product that has a line-in port, such as:
- Port/Connect
- Amp/Connect:Amp
- Five/Play:5
A turntable with built-in/external pre-amp can connect to the Line-In which becomes an audio source you can play to the Sonos device or other Sonos devices, which can also be grouped together for playing the audio throughout the Home.
Aauming your current setup is an S2 system, my suggestion would be to go for the ‘Five’ as you also get a great speaker too with that option, that’s if you can find use for the additional speaker of course.
If your system is S1, then also check here for S1 compatibility:
https://support.sonos.com/s/article/4786