The Earth is shaped like a ball. It spins around an imaginary line through its middle called its axis. This spinning is called rotation.
The Earth spins around once in about 24 hours. The Sun only lights up the half of the Earth that is facing it. On that half it is day. On the half facing away from the Sun it is night.
As the Earth turns, places move from the dark side into the sunlight (morning) and later from the sunlight into the dark (evening).
The Sun seems to move across the sky, rising in the east and setting in the west. But the Sun is not moving around us — we are turning!