What is an Order?
A grouping of line items tracking conversions and activity for the same ASINs.
What is an Order ID?
A unique identifier assigned to an order.
In the case of Google Ads via Amazon Attribution, the order ID will be the Google Ads campaign ID.
Why have my order IDs not been created in Amazon Attribution UI?
An Amazon order ID will only get created once your Google Ads campaign has at least 1 click. From the day of the click, it can take up to 48 hours for the corresponding order ID to be created in your Amazon Attribution account.