By default the side switch (right side of iPad above volume controls) is used to mute your iPad. You can change a setting which will allow this switch to be used to lock the screen and preventing it from switching to portrait or landscape when you move your iPad. This can be helpful if you are viewing something on your iPad and you want to lay the iPad on a table. Sometimes the iPad will change from portrait to landscape mode (or vice versa) when you lay it on a flat surface. This video is shown on iPad with iOS 6, but works the same with iOS 7. New video for iOS 7 coming soon!