Oh sh**t!! You have a man covered in blood with a chuck missing from his neck banging on your window, looks like you may have zombies! (Note: If the attacker is short wearing all green he is likely Irish and just drunk no need to shoot him in the head just call the cops.)
Step 1: Supplies! (you wont find these at Staples)
These are the basic things you will need
1. Non-perishable food.
3. Survival kit
4. Odds and Ends