In Hatchet, how does Brian try to start a fire?

In Chapter 6, Brian laments not having matches as he looks out at the vast amount of dry driftwood around the lake. He tries his best to think of how experts start a fire and begins to rub two sticks together. After ten minutes of rubbing the sticks together, the sticks are still cool to the touch, and he fails at starting a fire.
In Chapter 8, a porcupine enters his shelter and Brian throws his hatchet in its direction. The hatchet bounces off of the rock wall and creates tiny sparks. The next day, Brian wakes up and realizes that his hatchet is the key to starting a fire. He examines the wall of his shelter and notices that the hatchet struck the darker rock. Brian then begins to strike the blade of his hatchet against the dark rock to create sparks.
In Chapter 9, Brian takes patches of birchbark peelings and shaves them to make birchbark fluff. He then takes the fluff and forms it into a nest with a depression in the middle. Brian uses his hatchet to create sparks which land in the nest, and he blows on the embers to create fire.