Goto a bush and press F, this will gather sticks. You need to do this two times.
Press TAB and select the crafting tab at the top left hand side. Put the two bundles of sticks into the crafting table.
Click CRAFT, after this you will be able to place the campfire on the ground. Q and E rotates the campfire, Left Click puts the campfire down and Esc cancels crafting the campfire.
Next, Light the campfire with either a lighter or matches.
Now you have a campfire and can cook with it!
This is apart of one of the first quests. You will recieve the following: Board, Metal Tube, Catch Bolt and Insulating Tape.
Press Tab and put the items into the crafting table.
Equip the rifle.
Ensure you reload the rifle.
Remember: You have to reload after every shot.
Aquire the following Old Handle, Bicycle Sprocket and Insulating Tape.
Press TAB and put the items into the crafting table.
Equip the Axe.