Hi. Within this section, we're going to be building this fantastic app in which we're going to create a clone of Instagram. So, let me log out from here and I'm going to start telling by from scratch. So, we have a login page in which our user can give their email address and password, and if they match with the server, they can log in to the app. And let me show this by example. If I say larj@metallica.com and this user does not have this password, as you can see, we cannot sign in. And we can try with a user that doesn't even exist on the database like kirk@metallica.com and it won't even sign in again. If the passwords match, of course, we can sign in. What we can do, we can create a user called kirk@metallica.com by clicking the 'Sign up'. As you can see, we are inside. And I can go to Logout whenever I want. So, in the upload section, if I choose a picture from the gallery, I can write a comment and I can share it to see it on my feed later on. So, if I say 'Upload', it will upload this picture and the comment to the server, and it will immediately download it and show me in the feed. As you can see, there are different kinds of users sharing these pages, sharing these posts, and we can see them all. We can even like them if we want. Like here. So, when we tap on this 'Like', it goes to the Firebase database, it uploads the current value, and then just downloads it and immediately refreshes the Like label. So, in here, you can see my database, we are using Firebase. And in the authentication, we can see the users. And we're going to learn how to work with database, we're going to learn how to work with storage, we're going to learn how to work with authentication as well. So, if I can open this one more time. Furthermore, aside from Firebase, we're going to be learning how to work with tab bars, how to create custom use. Surely, this app will teach us a lot. After completing this section, you're going to be much more confident in iOS development, and you will be able to come up with an idea to create your own dream app on your own  with using this kind of technique. So, if you're ready, let's get started in the next lecture because we have a long way to go in this section.