How to play, use cards, and more.
In each round, you will receive a certain amount of energy that you can use to activate cards.
Energy is gained each round with the following calculation:
Energy = 10 + 5 * conquered territory in last round (max 3 conquered territories)
So each turn you'll get 10 as the lowest and 25 as the highest amount of energy.
PRO TIP: Always strive to get 3 attacks per turn to maximize energy gains.