As an AI language model, I cannot physically help you with the task of placing a star on the top of your Christmas tree. However, I can provide you with some guidance and tips. First, make sure your tree is stable and balanced on its base. Next, use a ladder or step stool to reach the top of the tree. Place the star gently on the topmost branch, adjusting it until it is centered and secure. Finally, make sure to turn the star so that the lightbulbs face outward, so that the light shines down on the tree and your room. Good luck!