|How do I change user/owner-rights on my files ?|
Use an FTP-program to change rights. You can also use the FileManager in the controlpanel.
Rights are applied to owner (you), group (webserver and internet) and all (other):
Recommended: CHMOD 640 : user:read/write - group:read - all:nothing
You don't have to apply any rights, just remember that you can write to "db" and "upload"; See info file on this subject in the root of your hostingaccount.