The Aux port on the soundbar is typically for a 3.5mm connection. If your tv has either a 3.5mm jack or the red/white left/right audio out, you can use a cable to connect it that way. There is a cable for both of those.
3.5 to composite audio: https://www.amazon.com/HDE-Triple-Co.../dp/B00CIC9KW2
3.5 to 3.5: https://www.amazon.com/Mediabridge-3.../dp/B004LTEUDO
From what I can tell by seeing some of the specs, it looks like you would need the second cable. I would need the model of the soundbar, though, to make sure. The tv, however, does say it has a 3.5mm jack. I just don't see any pictures of it.
Just examples, research for the right price and cable.