Strictly speaking, this is a marketing add-in rather than an admin add-in. But there didn't appear to be a separate category for those so I'm asking here. Google is promoting their customer review program, which provides a snippet of code to add to one's order confirmation page. This allows the customer to opt-in to place a review on your website listing on Google. Has anyone implemented this and can explain how to do it? I am up to my ears, as usual, with other demands and do not have time to figure it out.

Here is the Google code:

Code:
<script src="https://apis.google.com/js/platform.js?onload=renderOptIn" async defer></script>

<script>
  window.renderOptIn = function() {
    window.gapi.load('surveyoptin', function() {
      window.gapi.surveyoptin.render(
        {
          // REQUIRED FIELDS
          "merchant_id": 552139101,
          "order_id": "ORDER_ID",
          "email": "CUSTOMER_EMAIL",
          "delivery_country": "COUNTRY_CODE",
          "estimated_delivery_date": "YYYY-MM-DD",

          // OPTIONAL FIELDS
          "products": [{"gtin":"GTIN1"}, {"gtin":"GTIN2"}]
        });
    });
  }
</script>
There are links on this page for more information on integrating this:

https://support.google.com/merchants/answer/7106244

Many thanks to anyone who can steer me in the right direction.