After sending an initial 'welcome' email, Northern Trail Outfitters needs to configure Journey Builder to...

In Journey Builder, a 'Wait Until Event' activity is used to pause a journey until a specific event occurs, such as a purchase on a website. This allows the journey to continue with different steps based on customer behavior. For Northern Trail Outfitters, after the initial 'welcome' email, the journey can be configured to wait until the customer makes a purchase before proceeding to the next steps in the journey.

References:Salesforce Marketing Cloud Documentation on Wait Until Event