Well, you have a couple of options here. One is to use adhesive hooks and command strips to attach the lights to the window frame. This is a great way to keep the lights in place without damaging the glass or frames. Alternatively, you can use zip ties or cable ties to secure the lights to the window frame. These are more secure but may require some drilling or screwing into the window frame. Whatever method you choose, make sure to take proper safety precautions and follow all instructions and guidelines for the light strands you're using.