Make sure you have ecommerce tracking installed in your GA4 property and at least a couple of days of historical ecommerce data before you move forward.

Follow the steps below to see data for the first time customers in GA4:

Step-1: Login to your GA4 property and then click on ‘Reports’:

Step-2: Navigate to ‘Acquisition’ > ‘User acquisition’ report:

Step-3: Change your primary dimension from ‘First user primary channel group (Default channel group)’ to ‘First user source/medium’:

Step-4: Click on the drop-down menu under the ‘Event count’ metric:

You should now see a screen like the one below:

Step-5: Search for ‘Purchase’ event and then click on it to select it:

You should now see the data table for first-time customers:

This data table shows data for the first time customers because of the following reasons:

#1 ‘First user source/medium’ dimension: This dimension captures the source and medium through which a user first discovered your website or app. It remains constant across all user sessions and interactions.

#2 ‘New users’ metric: This metric counts the number of unique users who interacted with your website or app for the first time. 

#3 ‘Event count: Purchase’ Metric: This metric measures the total number of times the purchase event has occurred. When combined with the “New users” metric, it indicates the number of purchases made by users who are visiting your website or app for the first time

By combining these dimensions and metrics, the data table effectively shows the number of new users and the number of purchase events associated with these new users, thus providing a clear view of first-time customer activity.