Why are click box and button greyed out?

I have two images on a slide, and want the user to click on the correct image. In Apple Keynote I'd use a hyperlink leading to an effect and audio. Why are the options to add a place to click or a button to choose greyed out? Same with the insert menu.

I'm obviously missing something very basic, despite my videos and reading. Have been searching a long time for this basic answer! Thanks.

(Can't use Adobe Help pages as I can't enlarge the text to see it. ??)