If you consider using Guzaba CMS you probably do so because of its capabilities and flexibily for handling roles & permissions. Before you start with the installation have a look at the Security Model to find out more about the permissions, role and revisions and make sure this is what you need. It would be useful to read it no matter what role you will have in the configured CMS. Then you can proceed to the Installation Manual where basic tips are given on how to upload and configure the application before you start the actual installation.
Depending on how you plan to use Guzaba and your role in the system you will find useful these manuals (they are still work in progress):
As PhpDocumentor does not yet support php 5.3 (namespaces) thus no generated API documentation is available.