Ecwid

Tag Manager

On the Ecwid Control Panel:
Go to Sales Channels > Website > SEO
Edit the "Head meta tags & site verification", then paste GTM here.

Adding Value Tracking

Go to Configuration > Settings > General > Tracking & Analytics
Find "Custom tracking code on Order Confirmation page"
If this isn't enabled then enable this & then Edit code.

Add the below:

<script>
window.dataLayer = window.dataLayer || [];
dataLayer.push({'order_id' : '${order.number}'});
dataLayer.push({'order_value' : '${order.total}'});
dataLayer.push({'event' : 'order-submitted'});
</script>

The value will probably drop into Tag Manager formatted as currency (e.g. £120), so you can use a Custom JS variable to remove this like the below:

function() {

return Template:Order Value.replace(/[£,]/g,"");

}