require_once('/path/to/SwaggerClient-php/vendor/autoload.php');

<?php
require_once(__DIR__ . '/vendor/autoload.php');

$apiInstance = new Swagger\Client\Api\AppointmentApi(
    // If you want use custom http client, pass your client which implements `GuzzleHttp\ClientInterface`.
    // This is optional, `GuzzleHttp\Client` will be used as default.
    new GuzzleHttp\Client()
);
$request = new \Swagger\Client\Model\AddAppointmentRequest(); // \Swagger\Client\Model\AddAppointmentRequest | 
$site_id = "site_id_example"; // string | ID of the site from which to pull data.
$version = "version_example"; // string | 
$authorization = ""; // string | A staff user authorization token.

try {
    $result = $apiInstance->appointmentAddApppointment($request, $site_id, $version, $authorization);
    print_r($result);
} catch (Exception $e) {
    echo 'Exception when calling AppointmentApi->appointmentAddApppointment: ', $e->getMessage(), PHP_EOL;
}

?>