Is audio better through USB or optical?
Both will work fine, but optical has some major benefits over USB that just pushes it into first place. Not being affected by electrical and radio interference is a major advantage to me in the audio world. Personally I always use optical audio when possible.
How do I add optical audio to my computer?
Right-click anywhere in the Playback tab list, then click “Show Disabled Devices.” At this point, a device called something like “digital output” or “optical output” should show up. Right-click it and click “Enable” to switch it on.