Controls
With a one-page layout, the dock shows 1 page instead of the page buttons.
The page buttons step through the pages of your layout (Design > Layout). To see how many pages the PDF will
have, read the label above each page in the preview, for example Page 1 of 2.
Where the other canvas actions are
The dock only holds view controls. The rest sits in the header above the canvas:
Press ⌘ \ or Ctrl \ to show or hide the Edit panel and give the canvas more room.