Open the Monidenum website, along with the official TOTP Authenticator app — you'll need it to generate the codes. It's available for iOS on the App Store and for Android on Google Play.
Open the Monidenum website → Start → Enter your details → Authentication method → Select the "Guide for other authenticators" option → click the "Activate" button
Monidenum issues a unique 32-character secret key. Don't share it with anyone, so that your account can't be hacked.
The key needs to be added to the authenticator app you installed. The authenticator will then use the key to generate TOTP codes for your account.
Enter the code from the authenticator into the appropriate field on Monidenum. Keep an eye on the timer: once the time runs out, the code will change. You need to enter it in Monidenum and click "Continue" before the timer expires.
Done. Now, when logging in to your account, you'll need to enter your username, password, and a one-time TOTP code from the app.