The only audio input on your Panasonic HTS is analog audio. Without the TV model number I don't know what audio outputs is has.
If your TV has a headphone jack or analog audio output then use that connection to get sound from the TV to the HTS.
If the TV has digital audio output (optical or coax) then you will need a digital to analog converter like this one.
https
/www.parts-express.com/parts-express-dac-digital-to-analog-converter-(51-compatible)--180-999
Check the TV manual on how to use the output.You will not get digital surround sound so select a surround mode on the HTS that you like. Start with Dolby.