After listening to about 30% at the beginning, I found it too difficult and put the course aside in my library for a while, but after joining the challenge, I was able to complete it quickly. When I encountered parts I didn't understand while taking the course, I was able to supplement my learning by revisiting other courses in the Hanip series or checking the reference materials mentioned in the lectures. Especially while completing the challenge missions, I was able to identify which parts I didn't understand and fill in the gaps in my knowledge.