well, first your barricade your local walmart, then clean it out of all zombie infestations. there should be enugh food stuff to last for a least a few weeks. If your barricades are good enough, the Zombies won't see you in there so they on't attack. I n the mean time, you find all the ladders and what not in walmart, and build a bridge to the nearest building, clear that out, then rinse and repeat. After a while you should have your self A nice fortress.