No sound on my apple tv

I'm using a Samsung NOT smart TV with chromecast.

Like this?

The Apple TV app on the ‘Chromecast with Google TV’ dongle (2020 model) would use the general audio settings from the device. There is nothing to configure for audio for the Apple TV app specifically. Verify that the audio format is configured as Stereo for use with stereo speakers, else it might send a more complex audio stream that can’t be (fully) decoded.

Advanced sound settings for Chromecast with Google TV - Chromecast Help

If you are sending content from an iPhone or Mac computer to your TV via chromecast, then also specify the sending device. Apple apps on such home network relaying devices do not support chromecast (instead support AirPlay). Select third party apps on iPhone may support both.

Do you have the Apple TV box? If so, which model? Identify your Apple TV model - Apple Support

Or do you instead have the Apple TV app on a third party device? If so, what device and model?

What is your audio setup? And how is it connected?