1. Go to this page and download the library: Download airani/yii2-flysystem 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/ */
// Read from FTP
$contents = Yii::$app->flysystem->read('ftp://some/file.txt');
// And write to local
Yii::$app->flysystem->write('local://put/it/here.txt', $contents);