Explanation:

Page formatting and layout is mostly done in Sections.
Sections / Headers and Footers in Microsoft Word 2007-2013
The following may help as well:


Numbering Front Matter (Ribbon)
Bottom line, sections can have different page layout and numbering.

Text formatting and layout should be mostly done in Styles.
Understanding Styles in Microsoft Word

Automatic numbering will add yet another layer.
Numbering in Microsoft Word