Practice tip: Whittle out a piece of hard wood ( elm, ash, Osage, hickory etc.) to the same diameter as your front end segment outer diameter. Make the section 6-8 inches long. Then whittle down about 3-4 inches of that to a diameter that will fit inside the hollow section of your bamboo. Make sure it is snug. Be sure to wrap the bamboo with some artificial or real sinew to prevent splitting. Before you place it in, whittle the tip to the desired point.
Stone tip: same process as above except for the tip. You still whittle the tip down a bit, but you cut a groove to fit the end of your stone head. It's easier to explain with pictures. Holler if you would like that.