What is a challenge, and how do I succeed?

• Challenge is a content for users to collect certain cards within a fixed period of time.
  You can succeed in a challenge by collecting certain cards at the end of a given period of time.
  Cards required for challenge may be obtained through purchasing a pack or buying cards in the marketplace.
  
  
• There may be multiple challenges happening, so please go to the challenge page and check the ongoing challenge and rewards.