1. Log on to the online learning website of Harvard University (https://online-learning.harvard.edu/).

2. Browse the course catalogue and choose the course you are interested in.

3. Click on the selected course to view the course details, course duration, lecturers and other information.

4. Click the "Buy Course" button and confirm the purchase information on the pop-up shopping cart page.

5. Fill in personal information and payment information to complete the payment.