Use the mouse to navigate the menus and manage your army/buy new troops.

In-Game Controls:

Click the Drop Ship to deploy your troops.
Use the mouse to aim and shoot and select troops.
Use WASD or Arrow Keys to move troops around the level.
Group your troops using the 'Grouping' button.
Press [G] to toggle Grouping/Force Fire modes.
Press [T] to Teleport your grouped troops to the selected Troop's positions.
Press [+] or [-] to quickly switch between your troops.