How to get messages.getLongPollServer messages?

Question

PHP

Hello!
I can't deal with VKAPI, namely with longpolling

$messages = $vk->request('messages.getDialogs', array(
  'count' => '5',
  ));


  foreach ((array)$messages['response'] as $key => $value) {
    $uid =$value['uid'];
    $message = $value['body'];
//...продолжение работы

How to get dialogs via messages.getLongPollServer?