If you used Snow Leopard and you used two finger scroll then you are used to scroll direction natural being turned off in the system preferences. Go to settings (you can also access settings from finder then to the applications folder then to the settings application). Then click on track pad section in the settings then click on scroll and zoom then uncheck scroll direction natural. With scroll natural off if you slid two fingers down on the track pad that moves the page down and moving two fingers up on the track pad will move the page up. With scroll direction natural check on moving two fingers down on the track pad will move the page up and moving two fingers up will move the page down.