The Oozie site, http://oozie.apache.org/ , is built using Maven site plugin.
Check out the site branch.
Make the necessary changes
Build the site 'mvn site' to verify it builds correctly.
Check the built site under 'target/site' has the desired changes.
If you are not a committer or if changes are significant please open a JIRA and attach the patch for a committer to review (go to the Oozie JIRA, and select site as component of the JIRA issue).
The following steps must be done by a committer: