1. Go to this page and download the library: Download henter/wechat-oauth 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/ */
henter / wechat-oauth example snippets
use Henter\WeChat\OAuth
$oauth = new \Henter\WeChat\OAuth($appid, $secret);