Clicking on a picture with the mouse will take us to the title card of that stack. If the user clicked on the picture in the bottom right corner, they'd move to the title card of this stack. The second card is the title card. This time the background is red. The title itself is a text area.
Text areas can be any size.
Within them, you can color their background, use fonts, color the text, import text files, scroll text, and so forth. In this case, the text area background matches the card background, so only the text itself stands out. Finally, note the yellow box in the right corner. This is the button that moves the user to the next card. HyperStudio is most commonly used as a way to allow students to create their own projects.