Let’s get more familiar with 1 point perspective by doing some box drawings. Drawing boxes is by far the best way to learn perspective. Practice this a lot and as often as you can.
Draw a square or rectangle. You can actually place it bellow (bellow eye level), above (above eye level) or at the same height as the vanishing point (at eye level). It works just on all three positions.
This is how to draw a box in one point perspective. The box can be as wide tall and long as you want.
Up next are two other examples of boxes in one point perspective, but now with the box in front and above the vanishing point.