How can I use Cards to upgrade my Heroes and Towers?
As the Creeps grow stronger it’s important that your Heroes and Towers do so to!
To level up your troops simply select the sword icon (for Heroes) or tower icon (for Towers) that you can see on the right-hand side of your map screen and then tap on the Hero or Tower you would like to upgrade.
This will cause the upgrades window to pop up, in the lower left-hand side of this window you will be able to see how many cards are require for the upgrade.
If you have enough cards and coins simply select upgrade and your troops will be ready for battle!