To take advantage of creative controls, you must understand how autoexposure works. Then you can understand when and why you should over-ride its settings. Autoexposure is the most common exposure mode and the main one for point-and-shoot cameras. In this setting, the camera makes all the decisions for both the shutter and the aperture. You have virtually no choice. Generally speaking, the camera will select a shutter speed fast enough for hand-held shots and a select a corresponding lens opening.
Many cameras will let you lock in an exposure by pressing the shutter button down halfway. You can point the camera to a certain area and use that for your exposure settings. You should pick an area that is the same distance away as your subject, since the camera may also lock in the focus.
A simple technique with autoexposure is to point the camera down at the floor or ground that the subject is standing on. Find an area around his feet that is evenly lit, lock in that exposure and then bring the camera back up. This exposure will avoid problems with strong lights in the background or a bright sky.
Depending on your camera, the LCD monitor or viewfinder may give you a readout of the settings that are being selected. In this case, at least, you know what you are working with. If you do not like the settings, even basic cameras will often let you go to the next level of control, such as shutter priority or aperture priority.