To expand on jaydd's post, Turn on your Nexus 7 and you will be at your "Home Screen" then swipe left or right to reach the screen that contains your apps. Then press and hold the app icon until a notification box pops up and without releasing the icon drag it to the edge of the screen and the icon will be moved to that screen. Once you reach the home screen, release the icon and it will now reside on that screen, unless you decide to move it again. Pressing the center icon at the bottom of the screen, which looks like a house, will always take you to your home screen.
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