I have a Harmon Kardon Aura, but I don't see where to connect
It says it can use bluetooth.
Question marked as
Top-ranking reply
Make sure you have your speaker on and in pairing mode.
Go into Settings > Remotes and Devices > Bluetooth > Other Devices --the manufacturer name of you speaker should appear. (probably HK -something) Click on the name of that device and follow any onscreen instructions to pair the device with your AppleTV.
Here a support article with more information: https://support.apple.com/guide/tv/connect-bluetooth-devices-atvbbf148994/tvos