Alright, first things first, let's get the Firebase SDK into your app. This kit has Firestore and other cool Firebase services. Here's how you can add it:

1. Add Firebase to your JavaScript project by including these scripts in your app:

   ```HTML

   ```

2. Next, initialize Firebase in your app. Just replace the 'XXX' placeholders with your app's Firebase config object.

   ```JavaScript
   const firebaseConfig = {
   apiKey: "XXX",
   authDomain: "XXX.firebaseapp.com",
   projectId: "XXX",
   storageBucket: "XXX",
   messagingSenderId: "XXX",
   appId: "XXX"
   };
   firebase.initializeApp(firebaseConfig);
   ```

Now, let's set up Firebase Authentication. This is super important to link user profiles with authenticated users. Here's how:

1. Include the Firebase Authentication script in your app:

   ```HTML

   ```

2. You can use several methods for authentication. For example, using Google as a provider:

   ```JavaScript
   const provider = new firebase.auth.GoogleAuthProvider();
   firebase.auth().signInWithPopup(provider);
   ```

Alright, now let's set up the Firestore database.

1. Initialize the Firestore instance:

   ```JavaScript
   const db = firebase.firestore();
   ```

2. Create a new collection named 'users':

   ```JavaScript
   const usersRef = db.collection('users');
   ```

With Firestore all set up, you can now store user profile information.

1. Listen to the Firebase authentication state to know when the user's sign-in state changes:

   ```JavaScript
   firebase.auth().onAuthStateChanged(user => {
   if (user) {
   // User signed in, update or create the user profile
   }
   });
   ```

2. After the user has been authenticated, create or update the user document in the 'users' collection:

   ```JavaScript
   usersRef.doc(user.uid).set({
   name: user.displayName,
   email: user.email
   // Add more user profile information here
   }, { merge: true });
   ```

In the code above, user.uid is a unique identifier that Firebase Authentication assigns to each user, and we use it as the ID of the document. We also use the set method with merge: true to avoid overwriting the entire document.

You can retrieve the user profile information from Firestore and display it in your app.

1. Use the get function to retrieve the user document from Firestore:

   ```JavaScript
   usersRef.doc(user.uid).get().then(doc => {
   if (doc.exists) {
   const userProfile = doc.data();
   // Display the user profile information in your application
   }
   });
   ```

Remember that Firebase Firestore operations are asynchronous, so you'll need to use Promises or async/await to handle the responses.