Samsung Q950A soundbar set up problem

[TIU]

I read that the best connection is just one cable between the s/bar and TV - one hdmi cable from the hdmi arc on the s/bar to the hdmi arc on the tv, then external devices connected to the s/bar not the TV.
The manual recommends a high speed with ethernet cable and I've tried two different makes.

I tried that and had no sound and picture from the cable box. I connected the cable box back into the TV directly and got the picture back but no sound. I think I need a different hdmi cable - one with arc ? Well I've ordered one (I'm pretty sure it won't work too). The manual says the display should have D.IN alternating with TV Arc but only D.IN shows. So it's not recognising the arc connection. The hdmi 1 socket on the TV has arc so it should work.

For now I've connected the two with an optical cable so I have sound through the s/bar surround system (separate wireless sub and rear speakers) but I'd like to have it set up the best way. I'm not sure I'd get proper surround sound with the blu-ray player connected to the TV and the TV connected to the s/bar just with an optical cable.

[TIU]

I've got it working now. Under general settings on the TV, I switched Easylink on and 'HDMI Sound System' was added to the sound output list. So the TV finally recognised the soundbar. I've been able to connect the s/bar to the TV with a single cable - the hdmi arc connection and connect the virgin box and the blu-ray player to the s/bar.