Microsoft Authenticator App on your phone or tablet Download the App from Google or Apple store. The icon looks like this. Once downloaded open the app and if you have protected your phone by pass code, fingerprint, or face-recognition etc then you may be asked to do that to open it.
Once open look for the QR Code reader symbol which looks like this highlighted with the red box: If you click this icon, then it should open your camera ready for scanning a QR code for authentication.
If the camera does not show, then you need to check in your phone's permissions that the App has access to your camera.
Log in with your email and password. If you have not verified your account before, follow the instructions until the QR code is shown, then scan it with the Authenticator App as described above. Once you have scanned the code, your Authenticator App should 'Ping', open the app and add the 2 digit code displayed on the website.