The game lets you become a firefighter for one day. Actually, you are not the one who is going to go to fight the fire since all you need to do is to direct. The game starts when a fire broke up and you need to deploy all the vehicles needed to put out the fire.
Choose all trucks that you need and deploy them to the scene. Instruct them what to do and they will do the rest. After quite some time, you will know if you are successful in putting out the fire. The game repeats itself until you succeed at your first mission.