Use mouse to click unit card to select unit type.
Click on screen where you want to move unit.

Tips:
-You can place your unit using the Spacebar if clicking is hard.
-You can regen your units or hero by leaving them idle.
-Ranged units are good for backing up melee units.
-Attacking in groups is better than just sending units one by one.
-Use attack skill cards to help out your attacking or defending units.
-You can get new cards by leveling up your hero.
-Beware of counter attacks.