I didn't see this anywhere, so I thought I would mention it. I asked about this during delivery and my DS showed me. When you touch the App icons, the default behavior is to replace the current "top" app with the one you just launced. To get it on the bottom half of the screen you then "swap" using the double ended arrow at the center, right edge between the two apps. A direct way to launch an app onto the lower half of the screen is to touch the app icon, then without lifting your finger, swipe downwards (or "push the icon down the screen"). This will cause the app to launch into the lower half window.