Hi Dan,
The easiest way to do this is to go to the ribbon insert menu. Choose Page Number --> Bottom of page and then scroll down to the page X of Y section (about 10 items down in my list).

I just read that some people might not see galleries for page numbers, headers, and footers among other things. If that is the case for you search your help for "building blocks" and they should tell you how to turn this back on.

Hope this helps.