Lights are an important part of Christmas decorations, and they are usually placed on a Christmas tree to create a festive atmosphere. To put lights on a Christmas tree, you first need to decide how many strands of lights you want to use. Then, you need to determine where the lights will go on the tree. You can place the lights along the branches or around the trunk, depending on the look you want to achieve. Once you have decided where the lights will go, you can begin to string them along the tree.