when you first open it.
If you have opened the presentation and you couldn't see the yellow frame in the middle, your screen is too small for the "Large Screen" version. Go back and read about screen size on the home page, or simply enter the "Small Screen" version here.
If you see all three frames, but want to increase or decrease the height of one of them, you can RESIZE two frames by grabbing the border between them and dragging up or down. This requires a light touch with the mouse. You should see a double-headed vertical arrow when you engage the border with your mouse.