Your country is under attack and as one of the generals, you need to make sure that none of the invading forces can get in. If ever, they could get in, the people in the estate is in great danger. And that would lead to their demise, so it is your duty to make sure that none of the invading forces can enter the city.
The idea here is to protect the city and you can not let none of those truck invade the city. If ever, one of those trucks enter the city then you would lose some lives. Erect some towers that can put down those trucks. You could sell your towers once you are done with it. Of course, you should only do that when there is no other choices and that you would need a better tower to put in that place. Trucks come in waves, so you have a few seconds to spare before they can come. You need to place the tower strategically, so that they would work better. The trucks would be tougher and more could come, so you need to toughen up your defenses.
Are you ready to defend your country?