When you open up a PDF document, there’s these tabs on the left hand side. One of them is Pages. I somehow deleted that and I can’t figure out how to get it back, can anyone help? There’s a million help topics with the word “pages” in them!
You can right click on the left hand area and select “Restore Panels” (in the version I’m using, anyway).
Doesn’t work, can’t right click on that area 
If you just deleted the “Pages” panel, and the rest of the navigation pane is still there, go to the “View” menu, click on “Navigation panels,” and click on “Pages.” If the whole pane is gone, then View->Navigation Panels->Show Navigation Pane.
Yes, I got it back! Thank you!