To combine the answers above.
The cable you have connected sends DVD video from the Panasonic to the TV.
You will need to add cables to get audio from the TV to the Panasonic. The only input the Panasonic has is the analog aux input. If your TV has an analog audio or headphone jack then connect them with that. Most TVs only have digital audio output (usually optical) so you will need a digital to analog converter to connect them. Check the TV audio menu to make sure it can be set to output in PCM stereo. If not then you need a DAC which accepts 5.1.