The customer list is a screen for orders and access to the digital course product: who purchased it, paid for it, and whether access is available. It is visible to the account administrator.
To manage your customer list, open the Courses section, select a course, and navigate to "Users / Orders" in the bottom navigation. Here you'll find the "Grant Access" button, filters by access status and flow, column settings, and download options. From the order, you can access the course's students—this is the "Students" tab.
Payment provides access to the product, and the student sets the start date for their studies separately using the "Start Studying" button.