How to find the coordinates of the system in high school mathematics solid geometry?

Take the corner as an example. If the corner is at the lower left.

So how do you determine the coordinates of the desk lamp?

Then you can find three virtual planes through the desk lamp.

The first surface is parallel to the floor through the desk lamp.

The second side is parallel to the left wall (connected to the designated corner) through the desk lamp.

The third side is parallel to the front wall through the desk lamp (connected to the designated corner).

Three plane lamps must intersect with three lines (xyz) on the corner at three points, and these three values constitute the table lamp coordinates.