Getting layers to stick

I'm working on a teaching module that at one point involves a diagram of the human body. What I want is a relatively blank diagram initially where students can click on the various areas/organs to have more information appear. However, I want the layers to then stick. So if they've clicked on "heart" and all the information appears regarding the heart, that information stays there when they then click on "lungs" and by the end, once they've clicked on all the organ systems, they have a slide full of all the information. I seem to be unable to get these layers to stick, so to speak.

Similarly, I have some little boxes that are empty but when you hover over them, letters appear in them and if you click on them, they change color. I'd like to find a way to get those changes (letters and colors) to stay so you can eventually have all the boxes with different colors and letters in them.