Didn't the seller or Samsung jump in to warn you or help you set it up? The story makes me cringe since very few Samsung pass 5.1 to soundbars.

Call Samsung now at 1800SAMSUNG to ask if this model passes more than stereo as well as how to set it up.

Surround sound, even today takes a receiver on most setups with the usual connections like:
Source -> Receiver (for audio work) and then video is sent onwards to the HDTV.
An optical link from HDTV to Receiver for when the source is not HDMI.

I find it shameful that sellers and makers don't make this clear.