require_once 'google-api-php-client/src/Google/autoload.php'; // or wherever autoload.php is located
require_once 'google-api-php-client/src/Google/Service/Calendar.php';
require_once 'google-api-php-client/src/Google/Client.php';
session_start();

 $client = new Google_Client();
 $client->setApplicationName("Client_Examples");
 $client->setDeveloperKey('AIzaSyCBIkv4pLXaUFSIqi1vOFHNxtc1pkwv4xY');
 $client->setClientId('735801991462-je5ndaubh8a4sqba6bkl28rrnld6ufr0.apps.googleusercontent.com');
 $client->setClientSecret('GldF46q6M7LMBL4ji382cxXS');



$events = new Google_Service_Calendar_Calendar();

 //$event = new Google_Service_Calendar_Events();
$events->setSummary('Appointment');
//$event->setLocation('Somewhere');
$start = new Google_Service_Calendar_EventDateTime();
$start->setDateTime('2015-05-15T10:00:00.000-07:00');
//$event->setStart($start);
$end = new Google_Service_Calendar_EventDateTime();
$end->setDateTime('2015-05-15T10:25:00.000-07:00');
//$event->setEnd($end);
$attendee1 = new Google_Service_Calendar_EventAttendee();
$attendee1->setEmail('attendeeEmail');
// ...
$attendees = array($attendee1,
 // ...
 );
$events->attendees = $attendees;
$createdEvent = $service->events->insert("AIzaSyCBIkv4pLXaUFSIqi1vOFHNxtc1pkwv4xY", $event);
echo $createdEvent->getId();