You need to edit wp-config.php
Change only the following that is in Red:
// ** MySQL settings - You can get this info from your web host ** //
/** The name of the database for WordPress */
define('DB_NAME', 'Put Your Database Name Here');
/** MySQL database username */
define('DB_USER', 'Put Your Database User Here');
/** MySQL database password */
define('DB_PASSWORD', 'Put Your Database Password Here');