Top Star Jaeneung Seogo

Sang-Jun, a talentless idol trainee, wished to transfer to a new entertainment company. Then, the day he asked his director about it, Sang-Jun received a book which unlocks access to a "talent library", allowing him to quickly learn various skills.
With this book and his newfound "talents", Sang-Jun is going to become a top star!
(Source: KakaoPage, translated)