The default config.php file for a new CMS Made Simple install will look similar to this:

# CMS Made Simple Configuration File
# Documentation: /doc/CMSMS_config_reference.pdf
$config['dbms'] = 'mysqli';
$config['db_hostname'] = 'localhost';
$config['db_username'] = '**********';
$config['db_password'] = '**********';
$config['db_name'] = '**********';
$config['db_prefix'] = 'cms_';
$config['timezone'] = 'UTC';

If you want to add extra functionality or settings, you can add your lines at the bottom of the configuration file:

$config['db_prefix'] = 'cms_';
$config['timezone'] = 'UTC';
# add your own additional configuration lines below here...

You will find more information about the available parameters in the config.php Reference