• Head over to the Firebase Console and create a new Firebase project.
• Click "Add project" and just follow the setup wizard. It's pretty straightforward.
• Once you're done, click on "Add app" to choose your platform (Web, iOS, Android).
• Follow the instructions to integrate Firebase into your project. You'll need to download some configuration files and add a few dependencies.

• In the Firebase Console, find the "Authentication" section in the sidebar.
• Click "Get started" to enable Firebase Authentication.
• Under the "Sign-in method" tab, enable the providers you want to use (Email/Password, Google, Facebook, etc.).

• Add the necessary Firebase libraries to your project. For a web project, it looks like this:
    ```html
   
   
    ```

• Initialize Firebase with your configuration:
    ```javascript
    // Your web app's Firebase configuration
    const firebaseConfig = {
      apiKey: "YOUR_API_KEY",
      authDomain: "YOUR_PROJECT_ID.firebaseapp.com",
      projectId: "YOUR_PROJECT_ID",
      storageBucket: "YOUR_PROJECT_ID.appspot.com",
      messagingSenderId: "SENDER_ID",
      appId: "APP_ID"
    };

  // Initialize Firebase
  firebase.initializeApp(firebaseConfig);
  ```

• After enabling Firebase Authentication, you can tweak your registration flow to include extra custom user attributes. For example, to add custom attributes when using Email/Password authentication:

  ```javascript
  firebase.auth().createUserWithEmailAndPassword(email, password)
    .then((userCredential) => {
      // Signed in
      var user = userCredential.user;
      return user.updateProfile({
        displayName: "Custom Display Name",
        photoURL: "http://example.com/jane-q-user/profile.jpg",
        // Custom attributes can be stored in Firebase Firestore or Realtime Database
        // Let's use Firestore as an example here
        additionalUserInfo: {
          favoriteColor: "blue",
          birthdate: "1990-01-01"
        }
      });
    })
    .catch((error) => {
      var errorCode = error.code;
      var errorMessage = error.message;
      // Handle errors here
    });
  ```

• Use Firestore to store the custom user attributes:

  ```javascript
  firebase.auth().createUserWithEmailAndPassword(email, password)
    .then((userCredential) => {
      // Signed in
      var user = userCredential.user;
   
      // Add custom user attributes to Firestore
      return firebase.firestore().collection('users').doc(user.uid).set({
        favoriteColor: "blue",
        birthdate: "1990-01-01",
        // Add any other attributes you need
      });
     
    })
    .catch((error) => {
      var errorCode = error.code;
      var errorMessage = error.message;
      // Handle errors here
    });
  ```

• When a user logs in, retrieve the custom attributes from Firestore:
    ```javascript
    firebase.auth().signInWithEmailAndPassword(email, password)
      .then((userCredential) => {
        // Signed in
        var user = userCredential.user;

     
      // Get custom user attributes from Firestore
      return firebase.firestore().collection('users').doc(user.uid).get();
    })
    .then((doc) => {
      if (doc.exists) {
        console.log("User data:", doc.data());
        // Access custom attributes
        var userData = doc.data();
        console.log("Favorite Color: ", userData.favoriteColor);
      }
    })
    .catch((error) => {
      var errorCode = error.code;
      var errorMessage = error.message;
      // Handle errors here
    });
  ```