Quests are tasks that can be completed for rewards. There are 3 Daily Quests and 3 Big Quests available at any time. Your Daily Quests will refresh every 24 hours and a new Big Quest will become available 24 hours after the previous quest's completion.
For each new game you unlock, a game quest will also appear. Game quests have varied coins, gems and sticker rewards. Typically 3 game quests are available. They can be completed without a time limit. Once a game quest is completed, a new game quest will appear.
To complete a quest, you simply drag-and-drop the required stickers onto the Quest card. Once all stickers have been placed, the quest is automatically completed and the reward is given.
Game quests that are too hard to complete can be replaced with an easier one, but only once per day. Tap on the small button in the top right corner of a quest card in order to replace it. Daily quests cannot be replaced.
Any symbol stickers that were placed on unfinished Daily Quests or replaced Game Quests are returned to your inventory. You never need to worry about losing stickers! Also, symbol stickers can be removed from cards if you change your mind on where to apply your stickers.