Download the files
You can do composer but not necessary, if you want then you need https://getcomposer.org/
If you don't know how to use composer then go with your cmd to your folder where you extracted the downloaded github files and wirote composer
After you can use this code:
<?php
require_once __DIR__ . '/vendor/autoload.php'; // Autoload files using Composer autoload
use IPSConnect\Slave as IPSSlave;
$slave = new IPSSlave("http://yourboardurl.com",
"[your-master-key]");
if($slave->attempt("username/email", 'password'))
{
// Do something
}
?>
You need give the master key which you can find on your forum admincp Login Handlers
And lastly you can put POST method
If you can't do this, then I can help you via teamviewer. You need give me ID and password from teamviewer program in PM. IF YOU DON'T KNOW what is teamviewer then I recommend read first what can do with teamviewer.