How does Brian try starting his first fire?

Gary Paulsen's novel Hatchet is a story of survival. Thirteen-year-old Brian Robeson, traveling to see his father,  is stranded in the Minnesota woods when the pilot of the plane dies from a heart attack. Brian is left with no way to communicate, and very little hope for rescue. He must learn to survive on his own, with just a small hatchet and the clothes he is wearing, along with a few token items in his pockets.
Brian tries to create fire by rubbing two sticks together in chapter six, but he is unsuccessful. In chapter eight, he realizes that his hatchet may be the answer to creating fire. 

"The hatchet was the answer. That's what his father and Terry had been trying to tell him. Somehow he could get fire from the hatchet. The sparks would make fire. Brian went back into the shelter and studied the wall. It was some form of chalky granite, or a sandstone, but imbedded in it were large pieces of a darker stone, a harder and darker stone. It only took him a moment to find where the hatchet had struck. The steel had nicked into the edge of one of the darker stone pieces."

Brian found flint in the rock and was able to use it to create sparks. He still struggles to start a fire, though, even with the sparks. He tears up the twenty dollar bill he has, which is useless to him now. Then he eyes a birch tree and is able to use the papery bark as a fire starter. He has to shred the bark into threads and make a sort of nest out of it, so the sparks will catch the bark and still have enough air to survive. It takes him several hours, but he successfully makes his first fire in chapter eight.