The Mysterious Challenge is too difficult

This is my second round in the Mysterious Challenge. Without a dragon, I kept waiting until the seeds sprouted. (I was even confused about how to make the seeds at first). Just when I thought I could finally play, it ended lol. I have to open all the chests to get just one dragon egg... It takes too long to get even one dragon ㅠ_ㅠ The Mysterious Challenge is hard.. I guess I've been living in my camp too much. I need to progress through the world stages to learn some know-how ㅠㅠ