Adding "pages" is the difficult part in Word. It would be more accurate to say that you add
content which may or may not spill over to a new page. You'd have to add a manual page break or a section break to force a new page.
To re-use content, you can paste it in from a separate document or template, or you can store content in Building Blocks (an extension of AutoText entries in older versions of Word). A Building Block can contain anything that can be cut/copied and pasted in Word.
Preserving section formatting (headers, footers, page setup, newspaper columns) when pasting in content is far from straightforward. For more, see
http://word.mvps.org/faqs/formatting...thsections.htm.
If you know what elements should be in your document, you can add them in a single template for easy reuse. A template may consist of several pages if necessary.
I'm not sure if this is sufficiently specific...