Draw whatever image you want as your pop-up. For this example, we'll use a simple heart. Make one heart 6 inches high and two hearts that are 3 inches high.
Put the two lower edges of the small hearts at the bottom of your large heart. The bottom points of the small hearts will be about 1 inch above the large heart point. Tape the smaller hearts onto the big heart. You should see three heart lined up, with the large one in the middle. This is your template.
Trace the hearts onto the card stock. Cut it out. Create a crease in the middle of your large heart until the edges are pointing away from you.
Fold a 9-by-11-inch card-stock piece in half lengthwise. Open it.
Glue your small hearts to your card stock roughly 2 inches from its crease. When you close the display, your large heart will be flat; but when it opens, your heart will pop up.