Are you wanting to vertically center text? If so, be aware that this is a
section property, so you can't do it on a single page unless it's surrounded
by section breaks. On the Layout tab of Page Seteup, set the vertical
alignment to Center.
Unless you make that page a separate section. This is how one would go about
centering the title on the front page of a document: by formatting the front
page as a separate section.