The Digital Mini Artbook and Digital Mini Soundtrack are bonus content exclusive to the PlayStation 5’s Digital Deluxe Edition (or Upgrade) and Collector’s Edition. They can only be accessed through an app called the Square Enix Digital Content Viewer.
The app will be downloaded automatically when you install the game. If you have already downloaded the app, you can view the digital contents without having to download the app again; however, an Internet connection is required to use it.
Please note that the Digital Mini Artbook and Digital Mini Soundtrack are available in English and Japanese only.