integrate razorpay payment module in zenkart

Question

i am trying to integrate razorpay payment module in zenkart.

i added module in includes/modules/payment here is my code

  function process_button() {       
       $displayCurrency = 'INR';
    $api = new Api($keyId, $keySecret);
$orderData = [
    'receipt'         => 3456,
    'amount'          => 2000 * 100, // 2000 rupees in paise
    'currency'        => 'INR',
    'payment_capture' => 1 // auto capture
];

$razorpayOrder = $api->order->create($orderData);
$razorpayOrderId = $razorpayOrder['id'];
$_SESSION['razorpay_order_id'] = $razorpayOrderId;
$displayAmount = $amount = $orderData['amount'];
if ($displayCurrency !== 'INR'){
    $url = "https://api.fixer.io/latest?symbols=$displayCurrency&base=INR";
    $exchange = json_decode(file_get_contents($url), true);
    $displayAmount = $exchange['rates'][$displayCurrency] * $amount / 100;
}
return ' <script
    src="https://checkout.razorpay.com/v1/checkout.js"
    data-key="'.$keyId.'"
    data-amount="'.$amount.'"
    data-currency="INR"
    data-name="ganesh"
    data-image="https://s29.postimg.org/r6dj1g85z/daft_punk.jpg"
    data-description="desg ga"
    data-prefill.name=ganesh"
    data-prefill.email="xxxx@gmail.com"
    data-prefill.contact="999999999"
    data-notes.shopping_order_id="3456"
    data-order_id="'.$razorpayOrderId.'"
    data-display_amount="'.$displayAmount.'"
    data-display_currency="'.$displayAmount.'"
  >
  </script>
  <input type="hidden" name="shopping_order_id" value="3456">';
        }

i know my code is not working. i am new at zenkart i have php code for zenkart its working but i cant run this code zenkart. please help me to solve this problem