Stringing popcorn for a Christmas tree is a classic holiday tradition. To start, collect some popcorn kernels and a needle and thread. Then, thread the needle and tie a knot at the end of the thread. Next, pick up a popcorn kernel and push the needle through the middle of the kernel. Repeat this process, stringing each kernel one by one, until you have a long chain of popcorn. Finally, hang the popcorn chain on the tree, and enjoy the festive decoration.