FIle and folder permissions can be assigned by Workspace Owners to restrict whether a file can be accessed at all, to view or to edit. Permissions are cumulative - if you can write to a file the assumption is you should be able to view it as well. The default is no access.
For specific information on how to assign permissions see https://support.glasscubes.com/en/articles/1117723-file-and-folder-permission-restrictions
We do have Teams (groups) set up. The most wide-ranging is RCOphth Staff which should be used for any folder (usually) or file which should only be accessed by staff and not external people who may have a Glasscubes account because they are involved in a specific project or area of College work.