• First, sign in to the Firebase Console.
• Create a new project, or just pick one you already have.
• Head over to the Authentication section under the Develop category.

• In the Sign-in method tab of the Authentication section, turn on the authentication providers you want to use (like Email/Password, Google, etc.).
• Adjust the settings for each provider as needed.

• Still in the Authentication section, go to the Multi-factor authentication tab.
• Click on the Set up multi-factor authentication button.
• Follow the steps to enable MFA. Usually, you'll need to choose the types of MFA you want, like SMS-based verification.

• Customize options like the MFA enrollment policy, user experience, and fallback options.
• Save the settings after you're done configuring them.

• Go to the Templates tab in the Multi-factor authentication section.
• Customize the SMS message templates to fit your app's needs.
• Save the changes.

• Make sure the Firebase SDK in your app is updated to the latest version.
• Implement the necessary changes in your authentication flow to handle MFA. This often means updating your code to prompt the user for an extra verification step.

• When a user signs in, enroll them for MFA if they aren't already enrolled. Use the Firebase SDK methods to start the enrollment process.
• After successful enrollment, update your sign-in flow to request MFA verification based on the user's chosen method (like sending an SMS verification code).

• Thoroughly test the entire sign-up, sign-in, and MFA processes in a staging environment to make sure everything works as expected.
• Test various scenarios, including MFA enrollment, sign-in with MFA, handling incorrect codes, and fallback options.

• After deployment, keep an eye on the MFA metrics and logs in the Firebase console.
• Maintain the templates, update SDKs as needed, and handle MFA settings changes to ensure a smooth user experience.
• Respond quickly to any user issues or feedback regarding MFA.

This guide provides the steps required to configure Firebase Authentication with multi-factor authentication (MFA) in detail. Proper implementation and testing ensure enhanced security for your application.