Open Office User Guides
Has user guides for all parts of the suite. But, two chapters from the Writer Guide are particularly useful for dissertations, even if they are a little old:

• Ch12 - Creating Tables of Contents, Indexes, and Bibliographies 31-Dec-2006
• Ch13 - Working with Master Documents 31-Dec-2006

Tutorials for Open Office
This is a collection of a wide variety of formulas. Here are some that you may want to check out.

• Construction a Bibliography
• Master Documents
• Introduction To Templates
• Introduction To Indexes
• Create and Modify A Table of Contents
• Different Page Styles In a Document

Should you run into problems, here is the Advanced Writer Forum, in which people talk about such tasks as making books.