Apps are made up of screens, and each one performs a different function. Screens relate to apps in the same way pages relate to books.
When you first Manage your app, you're automatically taken to the screens section.
In the above example, the Contacts app is being managed, and by default, we are taken to its screens. Each tile you see ("Contact List, "Contact Preferences", "Customer Form") represents a single screen in the Contacts App.
At the top of the page, there is an option to create a screen, which you can read more about here.
The Contact List screen is the first screen listed. The star in the corner of the tile means this screen is the default screen that opens when a user clicks the app in the dashboard.
If you have permissions, you can change what default screen is chosen in the General section when managing the app.
Note: The default screen won’t always be the first screen listed, since screens are listed in alphabetical order.
Each screen also has a vertical ellipsis ( ⋮ ) allowing you to manage it. For more information, please see Screen Management.