Tutorials. The tutorials available at the Tutorials for OpenOffice Web site are helpful if you want to learn more about the use of OpenOffice.org suite's major components. Check the tutorials for Writer, Calc, and Impress.
User Guides. The official documentation is available online.
Inline Help.
You can also use the inline help which is
accessible through the → menu, or by pressing the F1 key. You
are bound to find the answers to your questions.