There are several ways to take a screenshoot on your Samsung Note II. You can do this by navigating to the screen you want to capture, press and hold the power button, then simultaneously press the home button. Hold them pressed until you hear a single shutter sound. You can find the picture in the Gallery.
You can also take a screenshot on your device using the S Pen. To do that, remove the pen from the bottom of the device, navigate to the screen you want to capture, click the side button from your S Pen, touch the screen with the pen and wait a few seconds until a shutter sound is played. The screenshoot will be available in Gallery.