Smushing full size images

When looking in the Attachment Details / Smush Stats and hovering over the "?" next to the full size image savings report, it says that Smush does not compress Full-Size images by default and that I can override this. However, I can't find where to do this. I am using a couple full size images that I want to smush. Yes, I know that there is a link on the Media Smush page that says, "Smush individual images via your Media Library" but when I click on that link it just takes me to the media library with no indication of where or how to do it.

Please provide me with specific instructions on how to smush a full size image.

Thank you.