You'll need the Tuya app on your phone (with your devices added) and a Tuya developer account to use this plugin. The Tuya developer environment is huge and a bit scary, but I found a video which should help. Follow the instructions in the video to link your Tuya phone app to your developer account so that the plugin can see your devices in the cloud.
https://www.youtube.com/watch?v=qVZJyHJsF9A
Devices must be manually created in Indigo; you'll need the virtual ID for each device (available on the app or in your developer account).