The config.inc.php provides the settings for the server-side scripts. It is build with PHP and provides a wide ability to setup the application to your needs
The groups.xml contains groups with defined policies and rules for different sections of FLOE. The policy concept prohibits actions by standard and via a rule it must be permitted to a group.
There are some files and folders that has to be configured before getting the system running. Some need special permissions others should be configured.