Factory radio harness 1st gen ms3

Whats up all. Forgive me if my question is answered elsewhere, if it is I couldn't find it.

Installed a CHEAP double din radio in my MS3. It turned on, everything functioned properly but not getting any sound from the speakers. The wire harness i purchased only had the one main connector though there is a smaller 16 pin connector in the dash with only 4 pins being used. Assuming that's steering controls but wasn't sure if it not being used was causing the issue with my speakers.

Sorry for the ignorance, new to this stuff.

 

I think it's missing stuff. There should be a vehicle specific harness. My Eonon was plug and play and even uses the steering wheel controls.