You should download and review the 2002 Legal User's Guide to Microsoft Word. It is available on my website. Original Legal Users Guide to Microsoft Word 2002 - Documents in Zip Format. It is no longer available on the Microsoft website.
That was written for Microsoft by leading consultants to the legal industry.

It is the basis for my Users Guide website. Here is the Templates chapter for that website. That chapter is original to me but provides links to the other chapters from the original. It was subsequently copied with permission to the Microsoft website.

I created these pages first for my own use because I added hyperlinks between chapters and to other resources not found in the original. The chapters on my site maintain the original content but have been expanded and also cover the ribbon versions. My chapters include many links to outside resources. Another original page is on Automated Boilerplate Using Microsoft Word. While that page talks about Building Blocks which are not in Word 2003, AutoText is a key component of Word 2003 and is extensively discussed in that chapter, as is AutoCorrect.

I had prepared an extensive answer going back to your original headers issue and styles but a stray mouse-click erased it before I could send. I will try to reproduce it but am sending this now before it likewise disappears.