During the WW2, thousands of soldiers become a hero, but the problem is that there are also thousands, who died during those days. Now, some lives might be save if there were medics caring for them on the battlefield. These medics should be equipped with a battle ready ambulance.
Drive your car as you can and kill those enemies on the field. Grab those money on the road. You will also earn money based on the distance that you traveled. Use the money to upgrade your car every time you can afford it. You will be needing it to progress further.