The Axis 2.0 website build system solely depends on Maven2. The build has been specifically tested to work with Maven version 2.0.7. To install Maven, download the distributions and follow the instructions in the documentation. Make sure you don't forget to add MAVEN_HOME/bin directory in the path.
Checkout the latest source using your favorite SVN client. If you are a committer, get a commiter check out.
During maven releases site should have been generated on target/site directory and no special action required. Further release process guide describes necessary steps to update Axis2 site with your new modifications.
In case if you want to generate site only you could run mvn site on root project of your local copy.