1. Go to this page and download the library: Download minkbear/captainhook 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/ */
// Retrieve the request's body and parse it as JSON
$input = @file_get_contents("php://input");
$event_json = json_decode($input);
// Do something with $event_json