To start a game, you'll need to tap on the 'Daily Challenge' option after tapping on "Play" in the main menu. By doing so, a screen will be displayed with the remaining time to complete the challenge, your progress, and the number of crowns you can receive as a prize for completing it.
In this mode, you'll have to complete four streaks of 5, 10, 15 and 25 questions that will need to be answered correctly and consecutively. When you complete each streak, you will receive crowns as a prize, and they will increase as you progress. Your progress will be saved and you'll be able to pick up the challenge another time, starting from the beginning of the streak you have reached. Bear in mind that since this is a daily challenge, the progress will be reset once the 24 hour deadline is up.
If your answer is incorrect, you'll lose a life and have to start all over again. If you have enough gold bars, you'll be able to pay in order to keep playing and not lose your turn.