Place the barrier on the road to stop the zombies and wait till they come. Shoot them with your primary weapon and switch to more powerful when you are in trouble. Upgrade the inventory to hold even bigger waves!
What would you do if you were in the center of a zombie apocalypse? Don't even think that you would be alone as people always stick together and build small groups to survive. However, your mission is to defend the road which leads to the camp where all other members are sleeping. Don't let those zombies pass through the border and stop them where they are!