If you are getting as frustrated as I was that
every document opens as A4 by default, do this:

Format >> Styles >> Catalog

Change the top dropdown to "Page Styles"
Select "Default"
Click "Modify"
Select the "Page" tab
Change "A4" to "Letter"

The style catalog is a handy location to
modify all the defaults and custom settings,
and everything is nicely categorized.

Bob