Squarespace

A business Account or higher is required to install tag manager.

Install Tag Manager

Go to:

Settings -> Advanced -> Code Injection

Enter the GTM to the Head & Footer

Contact Form

On the contact form, click:

Edit -> Advanced

within the Post-Submit HTML field enter:

<script>var dataLayer = window.dataLayer || [];dataLayer.push({'event' : 'contact-form-submitted'});</script>

Sales

Settings -> Advanced -> Code Injection
Scroll down to Order Confirmation Page & add the below:

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