Installing HA Voice Preview Ed. with HA Green & ZBT-2 - Voice not discovered

Greetings! Noob here. I have just set up HA Green & ZBT-2, and managed to operate a Sonoff ZBminiL2 light switch, via HA using my Windows laptop browser. I also have HA Cloud.

I have the HA Voice powered up by USB C, flashing in pairing mode, but it doesn’t appear in HA as an available device, integration or voice assistant. I expected it to show up as a discoverable device automatically as plug-n-play. Any suggestions gratefully received, Regards, Francis