This explains how the jury rigging works. This is a flamethrower that is incomplete (fuel tank missing) and found a way to launch flames even without a tank. If you guys want a full instructible on the flamethrower post in comments or PM me.
Step 1: Filling the Quote Reservoir
not having a tank to put gasoline in, using the black tube as a "resevoir" we can put a small amount of fuel that will be pushed out the barrel.