Setting up a an old LG Home Cinema audio system

[Markcelo]

Greetings,

So my dad had a really old speaker system including 5 speakers, a subwoofer, and a receiver, all the speakers are connected to the subwoofer and it's connected to the receiver via a "system cable" and it's connected via optical audio to the TV when I change the audio settings from the TV to optical audio there's no sound coming from any of the speakers.
Is there something I'm missing here or is there something broken?

The model name for the receiver is: LH-RH7506PA and for the subwoofer is LHS-75PA5A

Here's some pictures of the LG Home Cinema set: https://www.olx.pt/anuncio/home-cinema-lg-5-1-IDFBxpr.html

Regards