Begin Checkout

When user initiates checkout, fire below event

window._mp.safeExecute('evBeginCheckout', function() {
   eedl('mp_begin_checkout', {
      currency: 'INR', /* Currency of website */
      cart_id: '123', // mandatory
      value: 123.33, // float value of the item being viewed
      coupon: '<optional coupon>', // Leave this undefined if there is no coupon
      items: [/* Refer to Products Array page in reference below */],
      ev_source: 'gtm'
    });
  })();

If the event occurs in a iframe window, you need to fire the event using the below script.

window.top.postMessage({
      event_name: 'mp_begin_checkout',
      event_payload: {
            currency: 'INR', /* Currency of website */
            cart_id: '123', // mandatory
            value: 123.33, // float value of the item being viewed
            coupon: '<optional coupon>', // Leave this undefined if there is no coupon
            items: [/* Refer to Products Array page in reference below */],
            ev_source: '<Orign of the event>' // Example: Razorpay, Gokwik, etc.
          }
    },
    'PARENT_URL'
);

PARENT_URL is the url of the website.

Products Array