Shutter speed

Shutter speed is the amount of time the camera's shutter is open in order to control the camera's exposure to the light. Shutter speed is used for catching something in motion. The shutter speed works by setting the time it takes to take the picture so it can be fast as possible or as long as possible depending on what type of picture is trying to be shown. If you are trying to catch something in motion and freeze it, it can be 1/100 or faster and its measured by fractions of a second. If you're trying to create an artistic blur, you would try to have the shutter 1/60 of a second or slower. Basically, the faster the shutter results in a freeze motion shot but the slower the shutter results in a motion blur. Changing the shutter speed causes the light meter to either be underexposed or overexposed therefore you'd have to change the aperture first then the ISO (if needed) to zero out the light meter.

Aperture

Aperture is a setting in the camera that controls the opening of the lens to determine how much light goes in and controls the depth of field. The bigger the number, the smaller the opening. If the f stop is low then there is more light coming in and it has a shallow depth of field making the background of the subject blurry because it has selective focus. On the other hand, if the f stop is high then there is less light coming in and it has a greater depth of field which makes the background of the subject have more detail and is more clear because it has infinite focus. If the aperture is changed, the exposure triangle shift to one side either being overexposed or underexposed thus making you have to adjust the shutter speed or ISO to zero out the light meter. If the aperture is low then it would need a faster shutter speed but if the aperture is high then the shutter speed would need to be smaller to compensate for the amount of light coming in.