THANK YOU! That has worked a treat. I was head-scratching and never giving a thought to connecting up the tuner.on the Tuner you can see a cinch connection "EXT IN" . You will need the tuner to connect the PC to it. Either the ST-HD50 or ST-HD60 Tuner
https://i.ebayimg.com/images/g/YqAAAOSwGcllRKLp/s-l1600.jpg
You will need an adapter from 3.5mm jack to stereo cinch like:
https/www.amazon.com/Hama-00205110-Cinch-RCA-Audio-Connection/dp/B08YRZGZ85/ref=sr_1_6?crid=RPASEF1E419C&keywords=cinch+3.5+jack&qid=1701930208&sprefix=cinch+3.5+jack,aps,211&sr=8-6