Instructions
Play the game until the scene with the zombies attacking. After the cut scene ends, use the left analog stick to move and the right analog stick to look around the cabin.
Face Jesse Collins (the bald man with the hunting jacket) and press the "X" button to talk. He tells you to meet him at the truck so you can make your escape, but first you must gather three cans of fuel.
Walk to the back door of the cabin and press the "B" button to crouch. Press the "X" button to open the door and exit the cabin. As long as you remain crouched you make less noise, which helps to avoid drawing the attention of the zombies.
Follow the path to the left where you see a zombie with its back toward you. Sneak up to the zombie and hold the right shoulder button to execute it without making a noise.
Continue down the path, using the objective indicator as a guide, until you reach a clearing with two sheds. Execute the zombie with its back toward you and then walk up to the red can of fuel on the shelf next to the bolt-action rifle.
Press the "X" button to pick up the fuel, as well as the rifle and bullets. You will see a message stating that you need two more cans of fuel.
Continue along the path to the right using your objective indicator as a guide. Kill any zombies that you encounter until you reach another shed with an old truck inside. Pick up the second can of fuel on the ground next to the broken-down truck.
Follow the path to an area with six zombies. You can use the bolt-action rifle to pick off the zombies or just grab the can of fuel on the ground next to the wreck of the blue car and then leave the area. If you sneak, you can grab the fuel before the zombies notice you, so do this if you want to conserve ammo.
Follow your objective indicator back to Jess and the truck once you pick up the fuel can and see the message that you have found all the fuel cans.