Exactly where to paste the code?

I had the same question at first, then I paused, and thought about it for a second… the Description lists the ‘how to’…

“To embed a Qualtrics survey, simply paste the public URL to your survey on its own line in the editor. WordPress will do the rest.”

Which means, when you are on the page where you want to install the form, be sure you select the “Text” tab, not the “Visual” tab, and then paste the link where you want it, and then update the page.