Paste the code to you Framer website’s HTML field.
Next, go to your Framer website and find the HTML field. It is most likely in the form of an HTML/Code widget or module which you can find on Framer’s dashboard. Add it to your page, and paste the code you’ve copied before to the HTML field. Save and update, and that’s it, you should have Common Ninja’s Back to Top Button widget on your Framer website.