Provide any sample exaple how to crawl url

[Avishaidev]

Hey,
Is there any sample example how to get strart with this?
My code:
`use Spatie\Crawler\Crawler;

use Spatie\Crawler\CrawlObservers\CrawlObserver;

use Psr\Http\Message\UriInterface;

use Psr\Http\Message\ResponseInterface;

use GuzzleHttp\Exception\RequestException;

require DIR . '/vendor/autoload.php';

class MyCrawl extends CrawlObserver {
private $res;

public function willCrawl($url) {
    var_dump('willCrawl'.$url);
}

public function finishedCrawling() {
    var_dump('finishedCrawling');
}

  public function crawlFailed( UriInterface $url,RequestException $requestException,?UriInterface $foundOnUrl = null): void {
    var_dump('crawlFailed');
}

 public function crawled(UriInterface $url,ResponseInterface $response,?UriInterface $foundOnUrl = null): void {
    $html = $response->getBody()->getContents();
    var_dump($html);
}

}
$observ = new MyCrawl();

$url = 'https://www.facebook.com/Mhfootballclub/about/';

Crawler::create()->setCrawlObserver($observ)->startCrawling($url);`

What am i missing?