The Apache Roller documentation for any Roller version is available in the "docs" folder of your desired Roller version, obtainable from the downloads page of the Roller website. The documentation for the latest Roller release and for the newest nightly information (the latter, in OpenOffice format) is also available in the left-side menu on the Roller website. You may wish to work from these versions as they offer the most complete information, although some sections might not be relevant for older versions of Roller.
Contributed install guides
Here are some installation guides to help you get Roller up and running on Java EE servers and relational databases not covered in the Roller installation guide.