Thank you for reaching out! We're here to help you!
To connect your booster to the fan, open our app, tap the + button next to the External Sensor and then tap "Start". The trick is to scan the QR code using our app, and not the phone camera, we guarantee this time it will work :)
We have also attached the user guide to assist you.
Please let us know if you managed to connect your external sensor and do not hesitate to let us know if there is anything else we can help you with!