* The page linked above can also be reached from the Devices page by clicking the “Add Device” button at the bottom right of the screen and selecting “Zigbee Home Automation” then “Add Zigbee Device”.
Then put your device in pairing mode and it should be found.
FWIW, Tuya Zigbee devices can be really hit-or-miss and, in my experience, they are much less tolerant of a weak mesh than some other brands.
If you are new to Zigbee, you should really take a look at the Zigbee articles in the Community Cookbook, so you understand what is required for reliable function.