Unable to add a new page

Barb has already explained what the usual approach is.

What Page Break historically did was apply a Paragraph Format override (Pagination: Top of Page) to whatever para the cursor is in when you select I»PB. If that para is already at top of page, often nothing will happen immediately. In my copy of FM2020, it's doing nothing at all. But overrides are generally unwise stewardship, as they can be silently deleted (such upon any update to the containing para format).

If Disconnected Pages are present, then things can get complicated.

Hi @seank1234:

In most situations, when you need to add new content into the middle of the document, you just copy/paste the new content and FrameMaker will reflow the existing text to make room for it. You can also use File > Import > File if you prefer. 

~Barb

Whether you add a new page or not by inserting a page break would depend on the content. It's possible that the text flowed into some areas that did not have text before (most likely at the bottom of the pages).

You can add a disconnect page or insert multiple page breaks to the "empty" page. What is your purpose for the new page?