What is the priority of speed in photography? Be as detailed as possible. Thank you very much

Speed priority is actually the so-called shutter priority, that is, you manually set the shutter value, that is, exposure time and exposure compensation value. The camera will automatically set the aperture value according to the measured light intensity. The shutter value refers to the time difference between the camera front curtain opening and the Hou Lian closing. During this time period, the photosensitive element is constantly exposed, which is generally used to photograph the night traffic on the tripod frame, or to photograph the continuous or light painting of the water flow.