The Exposure Triangle
Aperture, shutter speed, and ISO make up the three sides of the exposure triangle. The work together to produce a photo that is properly exposed.
Shutter speed
SHUTTER SPEED MEASURE HOW LONG THE SHUTTER REMAINS OPEN FASTER THE SHUTTER SPEED THE LOWER THE EXPOSURE SLOWER THE SHUTTER SPEED HIGHER THE EXPOSURE.
Aperture
Aperture refers to the size of the circular hole in the lens that lets in light. The bigger the hole the more light that reaches the sensor. In fact, each time you double the area of that opening, you double the amount of light or increase the exposure by one stop. On the other hand, if you half the area of the opening, you half the amount of light hitting the sensor. And you guessed it; that will decrease the exposure by one stop.