Okay, so here's the quick-and-dirty of it...
To get a new page in the current page style, hit Ctrl+Enter. But if you're in columns, you need to be out of them first. Move your cursor to the very last position in the two-column section, then press Alt+Enter to get a blank line that is outside that section. THEN, do Ctrl+Enter.
The only time I use the menu to insert a manual page break is when I'm switching to a new page style (to get different headers/footers, usually).
Creating game materials? Monsters, spells, classes, adventures? This is the place!