Tournaments are a fun way to earn rewards!
Tournament events will ask you to use or earn a certain item in the time period given. Each time you earn or use the required item(s) on a level, the number you've contributed to your total will be shown in the rewards pop up.
To view your score, tap on the tournament badge in the top left of your screen to see your placement on the leaderboard. Your placement will be highlighted and you can view your score and your tournament player name.
Keep in mind that you have to be online when you win a level for the level’s points to count towards your tournament score.