You have to install the CutList extension in SketchUp and then run it from the Plugins menu on your saved file.
Feel free to ask if you have questions. It is often useful to see the SketchUp model so we can see what you’re working with. If you are reluctant to share the file publicly, you can send it to me in a private message by clicking on my name and then “Message”.
If you would find it useful, I can set up a “live” demo to show you how this sort of thing works. We’d just have to work out a time.