First, click on the online course from Products.
Then click on the Customers tab to bring up a list of customers:
Then click on a customer to see every lesson your customer has viewed or hasn't viewed:
Under any customer’s profile, click on the progress bar to see every lesson they’ve viewed.
Step 1: Click on Customers
Step 2: Search for your customer's email address
Step 3: Under "products & subscriptions" click the three dots to open the menu
Step 4: Click on "View progress..."