Read and respond 7

You can put the camera on aperture priority mode by finding the letter "A" or "AV" and turn it to that setting. When the camera is in aperture priority mode, the photographer controls the aperture and the camera chooses the appropriate shutterspeed. You should use this when you want to change the DOF in your photo.

You put the camera in shutter priority mode by finding the letters "Tv" or the letter "S" and turn it to that setting. In this setting the photographer chooses the shutter speed and the camera chooses the appropriate aperture. You should use this setting when you are photographing motion- you use a faster aperture to stop the motion and a smaller aperture to show motion. 

The best way to learn about these settings and How to use them is just to practice.