You can select a chapter from the dropdown on the sidebar.

(And while I’m at it, I might as well point out that the story is read from right to left.)

Or, if you prefer navigating through thumbnails, they can be found here:

• Prologue
• Chapter 1: Intro
• Chapter 2: Advertisement
• Chapter 3: Book
• Chapter 4: Return
• Chapter 5: Task

日本語訳はこちらです