Fred does not provide extra access control on top of the Alfresco functionality. Fred is fully transparent with regards to the access control implemented in Alfresco. Any access rights provided to a user or a group on a folder or a file will be applicable in the Fred application. Therefore, for example:
you will be able to find and see folders and files for which you have, at minimum, reading rights
you will be able to create folders when you have collaborator rights or higher
action commands for which you have permission will be enabled and vice versa action command, for which you have no rights on the selected file or folder, will be disabled.