Why was #Taeyeon at school after a while? 15 years since her debut. She had time to reveal great tips on how she became the top singer as Girls' Generation and a solo singer. Essential requirements to become a K-pop idol, how a group lasts long, planning an #ending fairy, tips on live shows, and so on. She's like the bible of idols. 'The Art of Girl Groups' defined by Taeyeon. Check it out on BAZAAR's YouTube video right now.