A:Answer You'll need to buy something called a digital to analog audio converter, (available through Amazon and probably eBay and other electronics stores) if you're trying to connect audio between a TV with optical audio only to a composite (white & red/ left & right) older audio system. Or, for a similar or even cheaper cost alternative, if you want to use one of your TVs HDMI ports, you can also use an HDMI (Digital) to component (analog) a/v converter & just don't hook up the video (yellow) component. For about $1-2 less (Amazon), you have a more versatile converter.
https://smile.amazon.com/Converter-Digital-Composite-Adapter-Support/dp/B07NRJW66S
(A composit to HDMI converter)