Fold the napkin diagonally in half, creating a triangle. Next, fold the napkin in half again, but this time, fold it so the pointy edge is facing down. Now, take the left side of the napkin and fold it towards the center, creating a triangle. Take the right side of the napkin and fold it towards the center, creating another triangle. Lastly, take the bottom edge of the napkin and fold it up towards the center, creating a triangle at the base. You should now have a Christmas tree-shaped napkin!