Again, in your text editor, open the 'control/defined.php' file and enter an admin user/pass. Examples:
define('ADMIN_USER', 'admin');
define('ADMIN_PASS', 'admin');
You can also restrict the login to certain IP addresses ONLY for security. Enter one or more IP addresses separated with a comma. Useful only if you have a fixed IP address. Leave blank for no IP restriction. Examples:
define('IP', '127.0.0.1');
define('IP', '127.0.0.1,78.150.204.108');
Note that this is not a server IP restriction.