1. Go to this page and download the library: Download wrapi/slack 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/ */
wrapi / slack example snippets
$slack = new wrapi\slack\slack(SLACK_API_TOKEN);
// Now you are ready to make API calls to Slack.