Unless you have a fancy soundbar with HDMI pass-thru, you will get (probably) stereo only, if the soundbar has additional RCA / AuxIn input.
If your DVD player has optical out, you can swap cables between the SkyQ box and the player.
If your DVD player has coax SPDIF out, there are converters which can make it optical.
Normally the SkyQ and DVD connect to the TV with HDMI.
The soundbar connects to the TV audio output (usually optical audio out).
You could also use an external HDMI input selector with audio extraction if the TV doesn't have audio outputs at all.