Thank you, that video confirmed that I needed to rotate the circular plate on the back of the device, unfortunately on my device it is totally flat. So...I mounted a thick piece of heavy duty double sided mounting tape to the circular cover plate, turned the device over, then simulaneously pressed and turned, and surprise the cover came off.
Well that's true for getting the device powered and paired. However, it's reporting humidity as 5%, not the 54% showing on the device, a Moes TS0201 manufacturer TZ3000_ywagc4rj. Seems the system generic zigbee temp/humidity driver does not support this device and I have to use @kkossev's Tuya Temp Humidity driver for correct humidity reporting. That driver is already in use on my system, so that's the next step.