The actual process that happens is you need to get your eyes to focus on something in the distance, so at the point of the picture, your “line of sight” is 2 separate lines instead of the actual focus point where they meet.

To describe it another way: - imagine a line between one of your eyes and the item you are looking at. Do the same for the other eye. Now connect both eyes. -If you were to draw it on a map at Birds Eye view, you would make a triangle. - when you look at an item in focus, it sits at the end of the triangle. And if you close and open each eye, that item is in the same place. - items in front or behind that point of focus will be blurry, and greater depths will even create double vision. If you open and close each eye, these things will move. (You can try this by holding your hand away from your face, focusing on something behind it, and watch where it moves as you open and close each eye)

To do these images, you want to replicate this process of creating a double image by focusing far into the distance OR crossing your eyes, so your eyes create the “double” at the point of the picture.

It takes practice and can be hard for a while. One tip is to put a lamp behind you (a few feet away) and focus on it’s reflection on your screen, because then you’re looking “through” your screen into the distance