Add new snippet klaviyo-tracking.liquid, paste code and include snippet {% include 'klaviyo-tracking' %} to product.liquid template

product.liquid

<script type="text/javascript">
    var _learnq = _learnq || [];
    var item = {
        Name: {{ product.title|json }},
        ProductID: {{ product.id|json }},
        Categories: {{ product.collections|map:'title'|json }},
        ImageURL: "https:{{ product.featured_image.src|img_url:'grande' }}",
        URL: "{{ shop.secure_url }}{{ product.url }}",
        Brand: {{ product.vendor|json }},
        Price: {{ product.price|money|json }},
        CompareAtPrice: {{ product.compare_at_price_max|money|json }}
    };
    _learnq.push(['track', 'Viewed Product', item]);
    _learnq.push(['trackViewedItem', {
        Title: item.Name,
        ItemId: item.ProductID,
        Categories: item.Categories,
        ImageUrl: item.ImageURL,
        Url: item.URL,
        Metadata: {
            Brand: item.Brand,
            Price: item.Price,
            CompareAtPrice: item.CompareAtPrice
        }
    }]);
</script>