How can l get administrated to regester or approve my account on Authenticator?

Normally you get MS Authenticator, add your MS account by logging into it through the app and then you have MFA codes available. You might get SMS or email (or even phone call) second factor steps depending on your account settings.

Then if you log into your MS account from a computer or phone you can go to your security settings and change your MFA to authenticator and get push notifications (or even go to a passwordless account).

What are you doing, precisely, and what happens when you do it? Step by step would be helpful.