Help with surround speakers connection to Soundbar

[Mouldrz]

Not latest models, but have WHM520V rear surround speakers. Have set these up and ready to go - the blue light is blinking and I've tried holding in the ID set button at the back for 5-6 seconds. I've plugged WiFi dongle into the soundbar. Then two separate YouTube videos have said to use the soundbar remote to get the soundbar to display ID Set and connect - either by holding down the volume button, or the top 'arrow' space for 5 seconds. Neither achieves anything - the first just mutes the soundbar and the second just shows the D.IN input currently used. Meanwhile the blue light on the rear speaker control just merrily blinks away unchanged.

Help!!