1. Go to this page and download the library: Download carstenwindler/config library. Choose the download type require.
2. Extract the ZIP file and open the index.php.
3. Add this code to the index.php.
<?php
require_once('vendor/autoload.php');
/* Start to develop here. Best regards https://php-download.com/ */
// load config from file with full path
$config = (new Config)->addConfigFile('/app/root/config/main_config.php');
// set the folder /app/root/config as your configuration folder
$config = (new Config)->setConfigPath('/app/root/config');
// load config from file /app/root/config/main_config.php
$config->addConfigFile('main_config.php');
// additionally, merge the config from /app/root/config/environment/develop.php
$config->addConfigFile('environment/develop.php');