Well, I think the first thing you need to do is to separate your question into two parts. The first and easiest to answer is how your eye detects light waves in the first place. This in turn can be broken down into how the eye focuses the light, and how this light is detected.
I'll start with the latter, the detection of the light. The basic idea is that there are
cells in your retina that are sensitive to visible light. These cells have special structures which contain
retinal, a molecule that, upon exposure to light, changes shape. This change in shape sets off a chain of events that eventually causes the cell to send a signal to the brain. This signal, along with many others from other photoreceptor cells, is processed by the visual system of the eye and brain to create the image.
Now, all of that above depends on the ability of the eye to focus light from one area of your vision onto a single spot on your retina. (So light from the center of your field of view is focused on the fovea, while light from 45 degrees off to the left is focused onto another part of the retina well off to the side from the fovea) In a healthy eye, the cornea does most of the focusing of the light and the lens simply provides fine adjustment to this focus. It's important to note that the image formed on the retina has little-to-no intrinsic information about distance. In other words, there's nothing your eye does to the light that allows you to determine distance to an object (other than the obvious job of focusing the light and allowing us to see in the first place). It's only by experience that the brain learns to accurately predict distances to objects, and it uses several methods to do so. A full list and their explanations can be found at the following wiki article:
https://en.wikipedia.org/wiki/Depth_perception
The 2nd part, how the visual system processes all this information, is beyond my ability to even begin to explain.
Boltzmann said:
. If two vacuum tubes used for the experiment have a different distance to us and emit not a continuous but just a short light impulse, how does this wave bring the information to the eye, that we can locate the source of the wave.
The direction is determined by where the light is focused on the retina. The light from one falls on a different area of the retina than the light from the other. This results in an angular separation between the two. Basically, you can think of yourself placed at the center of a sphere. If one tube is directly in front of you, at zero degrees, then the other will be off to the side and you would have to turn yourself or your eye X degrees to bring that 2nd tube to the center of your field of view. That angle is the angular separation between the two.
Now, obviously you and I don't go around thinking of things in terms of angles. In addition to the above, your brain does its best to find the distance to each object and then it combines the angle and the distance to determine which one is where. You yourself perceive all of this as one object being "about three feet to the left and two feet behind" the first.
All of that is a simplified, mathematical, half-wrong explanation, but I think it gives you some idea of the basics. I doubt your brain inherently knows what angles are, and it isn't that great at measuring things at a distance either. Through experience it manages to figure out how to interpret the placement of the light on your retina in such a way as to allow you to see correctly. In addition, there are many, many ways in which the brain can be fooled, as any optical illusion will show you.
