The 30, 7-minute videos of the 30-Day Challenge are "yours for life" once you have purchased them and they have been unlocked.
Here is how to access your 30-Day Challenge:
-- Go to http://students.holdenqigong.com
-- Use the email and password you used when you registered
-- At the introductory page, choose 30-Day Challenge
-- At the Welcome Page, on the top right, click on ALL LESSONS
-- On the Your Course Progress page, the videos that have been unlocked so far will have a gray checkmark next to them. The locked videos will have a grey lock symbol. (Videos are unlocked one day at a time)
-- Choose any of the grey panels to reveal the video titles
-- Choose the Day to open up the page with the video