The CMS Editors Toolkit is a good place to start. It is a set of help files for CMS editors and reviewers at the University. These instructions are the most up-to-date source of information about using the CMS.
Another resource is the Web Services blog. This contains articles on particular subjects written by Web Services staff.
If you need help with editing the CMS, need advice, or have found an issue or bug to report, request help on the Web Services website or email firstname.lastname@example.org