Jak zaimplementować curl api rest do php?

W wielu serwisach płatniczych i nie tylko używa się rest api,
nigdy wcześniej tego nie robiłem.
Dlatego bardzo proszę o pomoc w tym temacie.

curl -X POST https://secure.snd.payu.com/api/v2_1/orders \
-H "Content-Type: application/json" \
-H "Authorization: Bearer d9a4536e-62ba-4f60-8017-6053211d3f47" \
-d '{
    "notifyUrl": "https://your.eshop.com/notify",
    "customerIp": "127.0.0.1",
    "merchantPosId": "300746",
    "description": "RTV market",
    "currencyCode": "PLN",
    "totalAmount": "21000",
    "buyer": {
        "email": "john.doe@example.com",
        "phone": "654111654",
        "firstName": "John",
        "lastName": "Doe",
        "language": "pl"
    },
    "settings":{
        "invoiceDisabled":"true"
    },
    "products": [
        {
            "name": "Wireless Mouse for Laptop",
            "unitPrice": "15000",
            "quantity": "1"
        },
        {
            "name": "HDMI cable",
            "unitPrice": "6000",
            "quantity": "1"
        }
    ]
}'

Jak teraz zaimplementować ten kod żeby działało wszystko w php?

no dobra, zainstalowałem composer, pobrałem sdk i co dalej? test działa

<?php
/**
 * OpenPayU Examples
 *
 * @copyright  Copyright (c) 2011-2016 PayU
 * @license    http://opensource.org/licenses/LGPL-3.0  Open Software License (LGPL 3.0)
 * http://www.payu.com
 * http://developers.payu.com
 */
require_once realpath(dirname(__FILE__)) . '/PayU/vendor/openpayu/openpayu/lib/openpayu.php';
require_once realpath(dirname(__FILE__)) . '/PayU/vendor/openpayu/openpayu/examples/config.php';
$order = array();
$order['notifyUrl'] = 'https://test.com/PayU/vendor/openpayu/openpayu/examples/v2/order/OrderNotify.php';
$order['continueUrl'] = 'https://test.com/PayU/vendor/openpayu/openpayu/examples/layout/success.php';
$order['customerIp'] = '127.0.0.1';
$order['merchantPosId'] = OpenPayU_Configuration::getOauthClientId() ? OpenPayU_Configuration::getOauthClientId() : OpenPayU_Configuration::getMerchantPosId();
$order['description'] = 'New order';
$order['currencyCode'] = 'PLN';
$order['totalAmount'] = 3200;
$order['extOrderId'] = uniqid('', true);
$order['products'][0]['name'] = 'Product1';
$order['products'][0]['unitPrice'] = 1000;
$order['products'][0]['quantity'] = 1;
$order['products'][1]['name'] = 'Product2';
$order['products'][1]['unitPrice'] = 2200;
$order['products'][1]['quantity'] = 1;
$order['buyer']['email'] = 'test_buyer_email@payu.com';
$order['buyer']['phone'] = '123123123';
$order['buyer']['firstName'] = 'Jan';
$order['buyer']['lastName'] = 'Kowalski';
$order['buyer']['language'] = 'en';
/*~~~~~~~~ optional part DELIVERY data ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
//Add delivery informations
$order['buyer']['delivery']['recipientName'] = 'Robert Nowak';
$order['buyer']['delivery']['recipientEmail'] = 'test_buyer_email@payu.com';
$order['buyer']['delivery']['recipientPhone'] = '+48 456 123 789';
$order['buyer']['delivery']['street'] = 'Bar St. 155';
$order['buyer']['delivery']['postalBox'] = 'Warsaw';
$order['buyer']['delivery']['postalCode'] = '22-222';
$order['buyer']['delivery']['city'] = 'Warsaw';
$order['buyer']['delivery']['state'] = 'Masovian district';
$order['buyer']['delivery']['countryCode'] = 'PL';
?>
<!doctype html>
<html lang="en-US">
<head>
    <meta charset="UTF-8">
    <title>Create Order - OpenPayU v2</title>
    <link rel="stylesheet" href="../../layout/css/bootstrap.min.css">
    <link rel="stylesheet" href="../../layout/css/style.css">
</head>

<body>
<div class="container">
    <div class="page-header">
        <h1>Create Order - OpenPayU v2</h1>
    </div>
    <?php try {
        $response = OpenPayU_Order::create($order);
        $status_desc = OpenPayU_Util::statusDesc($response->getStatus());
        if ($response->getStatus() == 'SUCCESS') {
            echo '<div class="alert alert-success">SUCCESS: ' . $status_desc;
            echo '</div>';
        } else {
            echo '<div class="alert alert-warning">' . $response->getStatus() . ': ' . $status_desc;
            echo '</div>';
        }
    } catch (OpenPayU_Exception $e) {
        echo '<pre>';
        var_dump((string)$e);
        echo '</pre>';
    }
    ?>

    <h1>Request</h1>

    <div id="unregisteredCardData">
        <?php var_dump($order); ?>
    </div>

    <table class="table table-hover table-bordered">
        <thead>
        <tr>
            <th colspan="2">Important data from response</th>
        </tr>
        </thead>
        <tbody>
        <tr>
            <td>Order status</td>
            <td><?= $response->getStatus() ?></td>
        </tr>
        <?php if ($response->getStatus() == 'SUCCESS'): ?>
            <tr>
                <td>Order id</td>
                <td><?= $response->getResponse()->orderId ?></td>
            </tr>
            <tr>
                <td>Redirect Uri</td>
                <td><a href="<?= $response->getResponse()->redirectUri ?>"><?= $response->getResponse()->redirectUri ?></a>
                </td>
            </tr>
        <?php endif; ?>
        </tbody>
    </table>
    <h1>Response</h1>

    <div id="unregisteredCardData">
        <?php var_dump($response); ?>
    </div>
</div>
</html>

wprowadziłem to i otrzymuję to

Create Order - OpenPayU v2

SUCCESS: Request has been processed correctly.
Request

D:\wamp\www\test.com\payment-payu.php:78:
array (size=10)
  'notifyUrl' => string 'https://onecoingrants.com/PayU/vendor/openpayu/openpayu/examples/v2/order/OrderNotify.php' (length=89)
  'continueUrl' => string 'https://onecoingrants.com/PayU/vendor/openpayu/openpayu/examples/layout/success.php' (length=83)
  'customerIp' => string '127.0.0.1' (length=9)
  'merchantPosId' => string '145227' (length=6)
  'description' => string 'New order' (length=9)
  'currencyCode' => string 'PLN' (length=3)
  'totalAmount' => int 3200
  'extOrderId' => string '5cc3e202bcf703.49950936' (length=23)
  'products' => 
    array (size=2)
      0 => 
        array (size=3)
          'name' => string 'Product1' (length=8)
          'unitPrice' => int 1000
          'quantity' => int 1
      1 => 
        array (size=3)
          'name' => string 'Product2' (length=8)
          'unitPrice' => int 2200
          'quantity' => int 1
  'buyer' => 
    array (size=6)
      'email' => string 'test_buyer_email@payu.com' (length=25)
      'phone' => string '123123123' (length=9)
      'firstName' => string 'Jan' (length=3)
      'lastName' => string 'Kowalski' (length=8)
      'language' => string 'en' (length=2)
      'delivery' => 
        array (size=9)
          'recipientName' => string 'Robert Nowak' (length=12)
          'recipientEmail' => string 'test_buyer_email@payu.com' (length=25)
          'recipientPhone' => string '+48 456 123 789' (length=15)
          'street' => string 'Bar St. 155' (length=11)
          'postalBox' => string 'Warsaw' (length=6)
          'postalCode' => string '22-222' (length=6)
          'city' => string 'Warsaw' (length=6)
          'state' => string 'Masovian district' (length=17)
          'countryCode' => string 'PL' (length=2)
Important data from response
Order status	SUCCESS
Order id	KSWKDNMXMK190427GUEST000P01
Redirect Uri	https://secure.payu.com/pay/?orderId=KSWKDNMXMK190427GUEST000P01&token=eyJhbGciOiJIUzI1NiJ9.eyJvcmRlcklkIjoiS1NXS0ROTVhNSzE5MDQyN0dVRVNUMDAwUDAxIiwicG9zSWQiOiJ6RGVubjhoTiIsImF1dGhvcml0aWVzIjpbIlJPTEVfQ0xJRU5UIl0sInBheWVyRW1haWwiOiJ0ZXN0X2J1eWVyX2VtYWlsQHBheXUuY29tIiwiZXhwIjoxNTU2NDI3NjQ4LCJpc3MiOiJQQVlVIiwiYXVkIjoiYXBpLWdhdGV3YXkiLCJzdWIiOiJQYXlVIHN1YmplY3QiLCJqdGkiOiJmZGFmM2VjNS0zYjMxLTQ0ODEtODkzOC1iZTYzNzM2NWRmNDIifQ.MxkNSthFiXgziAEHkvdABe-t2vCSOu_cHzj3mFGgSEs
Response

D:\wamp\www\test.com\payment-payu.php:108:
object(OpenPayU_Result)[5]
  private 'status' => string 'SUCCESS' (length=7)
  private 'error' => string '' (length=0)
  private 'success' => int 0
  private 'request' => string '' (length=0)
  private 'response' => 
    object(stdClass)[3]
      public 'orderId' => string 'KSWKDNMXMK190427GUEST000P01' (length=27)
      public 'extOrderId' => string '5cc3e202bcf703.49950936' (length=23)
      public 'status' => 
        object(stdClass)[9]
          public 'statusCode' => string 'SUCCESS' (length=7)
      public 'redirectUri' => string 'https://secure.payu.com/pay/?orderId=KSWKDNMXMK190427GUEST000P01&token=eyJhbGciOiJIUzI1NiJ9.eyJvcmRlcklkIjoiS1NXS0ROTVhNSzE5MDQyN0dVRVNUMDAwUDAxIiwicG9zSWQiOiJ6RGVubjhoTiIsImF1dGhvcml0aWVzIjpbIlJPTEVfQ0xJRU5UIl0sInBheWVyRW1haWwiOiJ0ZXN0X2J1eWVyX2VtYWlsQHBheXUuY29tIiwiZXhwIjoxNTU2NDI3NjQ4LCJpc3MiOiJQQVlVIiwiYXVkIjoiYXBpLWdhdGV3YXkiLCJzdWIiOiJQYXlVIHN1YmplY3QiLCJqdGkiOiJmZGFmM2VjNS0zYjMxLTQ0ODEtODkzOC1iZTYzNzM2NWRmNDIifQ.MxkNSthFiXgziAEHkvdABe-t2vCSOu_cHzj3mFGgSEs' (length=466)
  private 'sessionId' => string '' (length=0)
  private 'message' => string '' (length=0)
  private 'countryCode' => string '' (length=0)
  private 'reqId' => string '' (length=0)

w którym pliku zmienić parametry api? bo w tym nie ma