To put Christmas tree lights on a tree, you'll first need to make sure the tree is stable and secure. Then, you can start by attaching the first string of lights at the top of the tree and working your way down, wrapping the lights around the branches in a spiral pattern. Make sure to space the lights evenly so the tree has a balanced and even appearance. Once you've finished with the first string, you can move on to the second string and follow the same process until the entire tree is covered in lights. Finally, plug the lights in and enjoy your beautiful, illuminated tree!