Aperture is a device in the lens of the camera controls how much light is let in the the picture. In the picture to the right, the aperture is low resulting in a darker picture. In the picture above, the aperture is higher, again resulting in a lighter picture.
Shutter speed is the length of time the shutter is open. This is useful when you are taking photos of sports, or things with lots of movement. If you have a lower shutter speed (1/4) the picture will be blurry because the shutter is open longer. The picture on the left has a higher shutter speed, which makes the picture clearer.
ISO speed is how sensitive the camera is to light. If the ISO speed is small (100) the picture will be dark (left picture). If the ISO speed is high (6400) the picture will be bright (right picture).
Exposure is the amount of light allowed to fall on each unit area of a photograph. You can make the picture brighter or darker.
White balance adjusts the lighting to make the colours balanced. The picture on the left is good white balance because the colours are normal (not yellow or blue). The picture on the right is bad white balance because the colours are yellow.
Optical zoom is located on the lens. When you turn the dial you can make the object look bigger. This will help show detail on the object. The picture on the right is at a bigger optical zoom than the one on the left.
Auto focus is when the camera focuses on the object in the picture without you having to do it. Manual focus is when you have to turn the dial on the lens in order to make the object in focus. Good focus is when a picture is clear.
The priority settings are used to make part of the picture sharp or blurry. For example if you are taking a landscape picture you would want to foreground and the background in focus. When taking a picture of a specific thing in the picture you would want it to be sharp and the background to be blurry.