To use this method, you must first have set up the authenticator app with Unipass through the "my account" page.
First click "authenticator app setup".
Then click "how to setup the authenticator app", which will present instructions and a QR code/setup key.
You can use Google Authenticator, Microsoft Authenticator, or Authy to scan the code/input the setup key. This will generate a 6-digit passcode, which you can enter into the Unipass website, then click Enable.
Once set up, you can use the authenticator app, by entering your username/email and the 6-digit code generated by your authenticator app to log into websites via Unipass.