Now we need to add the vents. I used two cheapo heating vents from Home Depot. I think they were $4 a piece. I used my skill saw and cut a whole in the roof and also one in the center of the floor under where the burner will be. The two of these will make it much easier to regulate the temperature.
Note: In this picture, the one in the floor is not cut but you can get the idea by seeing the one in the top.