(1) Eye level is where your eyes are, the height of your eyes.

(2) When an object is below an eye level → You see the top surface of the object.
     When an object is on an eye level → You see the sides.
     When an object is above an eye level → You see the bottom.

(1) Define an eye level.

(2) Put a vanishing point on the eye level.
     (vanishing point is a point which exists on the horizon line. it can be placed anywhere on an eye level, and everything in a canvas converses into the point.)

(3) Extension of the lines meets at the eye level.

(4) In 1 point perspective, horizontal lines are always parallel to each other, as are vertical lines.

(5) When an object is below an eye level → You see the top surface of the object.
     When an object is on an eye level → You see the sides.
     When an object is above the eye level → You see the bottom.
     You don’t want to forget this idea.

(6) This method can be applied to a complex object as well.