Entire piece displayed on single line; breaks ignored

Hi, someone sent me a score that is displayed in it's entirety on a single system on a single very wide page. I want to display this piece as a regular score with multiple systems below each other and split out over several pages.

What kind of setting controls this display format? When scrolling, the key signatures and instruments are displayed in a fixed position on the left of the page in blue, while the rest of the piece scrolls horizontally beneath it. Even manually inserted line or page breaks are ignored.

I have searched extensively in the handbook, and have tried changing every setting that seems appropriate, but I can't find a way to get this score to display normally.