How to copy pages/sections from one Pages document to another?
I think this used to be an option in the old version of pages - where you could just highlight a page copy it and past it over to a new doc. 

Now you would need to select all content on a page copy that and past it over to a new already existing page on a new document. 

To select content: if you open the pages window up (larger than the white page) you can drag a selection box over the content you want, starting from off the page.