You will need to create a directory for OJS to store its submission files in. This should not be in a web-accessible directory, as then it would be possible for private files to be accessed online (eg. by savvy users attempting to point directly to the file in question by typing http://www.example.com/files/journals/1/articles/1/submission/review/1-3-1-RV.doc into their browser). If, for example, you have placed the OJS application files in /var/www/html/ojs/, you will have to create this directory outside of /var/www/.

You will then need to grant file permissions so that the web server can administer and write to the public/ and cache/ subdirectories of the OJS installation path, the files/ directory you just created, and the config.inc.php configuration file. The specifics of setting permissions will depend on your web server configuration, i.e. whether PHP scripts run SetUID. The install page will warn you if you don't have the appropriate permissions.

In the above example, config.inc.php isn't writable by the server (which is not strictly necessary for normal functioning, although it is for automatic installation), and neither is the cache/t_cache/ directory. Remember, all directories within cache/ must be writable by the server.