change order status with webhook from payment gateway -- 3

I have a Yii transactional system (Karenderia system) currently, the system works like this: User go to checkout->payment gateway flow->payment success->redirect back to website and order is placed. The problem with this flow, is that if user close the payment thank you page before being redirected back to website, order is not placed. To solve this, I need to use webhooks from payment gateway, so I can capture the payment success payment and change status of the order to paid in that moment, and not when user is redirected back to site. The payment gateway is MercadoPago and webhook documentation is here: [login to view URL] Video attached.