Here are links to a few documentation links that could be resourceful for a user:
Welcome to GMAT! We're glad you're interested in using our software. This wiki has many resources to help you get up and running.
The following links contain some introductory information on what GMAT can do and how to obtain it.
See the following pages for documentation, tutorials, and training:
If you need more help, see the following pages for information on submitting a bug report or feature request, or for contact information.