How do I make the page numbers on different positions?============

[Guest]

The majority are on the top center,
but for those of the first pages of each chapter, how do I put
them individually on the botton center?

 

[Guest]

If you have next-page section breaks between each chapter, then you can
select "Different first page" headers and footers from the File | Page Setup
| Layout.

 

[Daiya Mitchell]

You use a First Page Header and set the page number in a different place on
the first page. This article will explain all you need to know to do that,
and more besides:
http://word.mvps.org/FAQs/Formatting/NumberingFrontMatter.htm