In order to track purchases effectively, at minimum your Google Tag Manager container must have a variable containing a unique identifier (such as an order id) for deduplication. While not required, a revenue variable will unlock additional metrics such as Average Order Value (AOV) and Return on Ad Spend (ROAS).

Navigate to Workspace > Variables and find the User-Defined Variables area of the page.
If the variables have been setup previously, you should see them in the list.
Take note of the variable names as the code we provide by default will have {{Transaction}} and {{Revenue}} entered as placeholders. In this example, Revenue is a match but Order ID is different. You will want to replace every instance of {{Transaction}} in the code we provided, with {{Order ID}}.

Here is an example of what changing the variable name from one value to another could look like.

before

<script type="text/javascript">
window.orion_config = {
account: 00000,
transaction: '{{Transaction}}',
revenue: '{{Revenue}}'
};
</script>

after

<script type="text/javascript">
window.orion_config = {
account: 00000,
transaction: '{{Order ID}}',
revenue: '{{Revenue}}'
};
</script>

Getting Started