Where is the autoplay function for the port on the Sonos S2 App?

Where is the autoplay setting for my port in the S2 app? Every time I play a vinyl on my TT which is connected to a Marantz amp and then to my port which streams music to my era 300’s. When I turn the vinyl over, my port pauses and I have to press 'play' again on the line in screen in the app. It is so annoying. I believe this shouldn't happen if there was an auto play function. I have read all Sonos instructions and it keeps telling me to set auto play on the port. Guess what? I can't find it anywhere. Does anyone know where I can find the auto play function for my Port? Many thanks.