You just need to download the extension to the appropriate browser and it should then start popping up on the listings. Here is the link: https://keepa.com/#!addon
Just make sure you click the right browser, and it should add it for you. If you still do not see it, you may need to "turn on" the extension in your browser settings.
Bob also has a video in the course under the “Tools” section titled “Keepa” that walks you through the whole process.
Where is the graph?
Why can't I see Keepa?
How do I add Keepa as an extension?