Sample client

Your first class:

<?php

include '../src/openkm/OpenKM.php';

ini_set('display_errors', true);
error_reporting(E_ALL);

use openkm\OKMWebServicesFactory;
use openkm\OpenKM;
use openkm\bean\Folder;

class TestOKM {

    const HOST = "http://localhost:8080/OpenKM/";
    const USER = "okmAdmin";
    const PASSWORD = "admin";

    private $ws;

    public function __construct() {
        $this->ws = OKMWebServicesFactory::build(self::HOST, self::USER, self::PASSWORD);
    }

    public function test() {
        $folders = $this->ws->getFolderChildren("/okm:root/SDK4PHP");
        foreach ($folders as $folder) {
            var_dump($folder);
        }
    }

}

$openkm = new OpenKM(); //autoload
$testOKM = new TestOKM();
$testOKM->test();
?>