One of the essential parts of the game is the Task board. You can find it on the main screen at the left bottom corner. Slide from right to left to look through available tasks, complete them, and get valuable rewards along with experience to move to the next level!

The other thing that should be mentioned is the Daily tasks. It's the first card in the menu where you can complete daily tasks for a reward. Complete five in a row and get an even bigger reward!