I tear my hair out when I read most descriptions of how a VOR works. Not to say any of them are wrong (the actual technical ones are usually wrong but that doesn't matter). As an electronics engineer I even once did a design of a VOR receiver, many years ago. But I suppose if you are going to write a book called "VOR and ADF", and you want to sell it in the common pilot shops, then it needs to have a price tag allowing a decent trade margin, so it needs at least 200 pages...
For a simple explanation, I like to think of a VOR as a lighthouse, but one working in radio waves and not with visible light.
With one twist on the real lighthouse though: it has different colour glass windows fitted on different bearings, so if you see e.g. red light you know you are somewhere around say 230 degree bearing from it.
That's what a VOR gives you: a rotating beam, whose instantaneous bearing is encoded onto the radio signal. The aircraft receiver decodes the information and presents the bearing you are sitting on. Very simple!
The difficult bit is that the receiver does't give you the bearing literally e.g. "230 degrees". (You can get that but it costs extra) VORs go back to the 1950s, before transistors so everything had to be simple, and very importantly they were designed for flying long cross country legs. So the receiver is designed to facilitate the flying of long legs, and the presentation thus consists of the bar that moves left to right, and the two flags. This is what confuses people. The contentional VOR receiver presentation is good for long legs, and a real pain for more practical stuff like position fixing.
Everything which the receiver presents (i.e. the bar deflection and the flag settings) is derived solely from the received signal (the radial) and from the position of the OBS dial. The rule used is simple enough but almost impossible to describe without a diagram.
In the intended use (flying long legs) it's very simple to use. The problem comes when trying to sit the IR exams; in those they throw at you trick questions about which quadrant etc you are in. There are various clever ways of working those out. But
AFAIK this stuff is never used in real flying.
If you fly around with one of those ICOM handheld radios which receive a VOR and display the radial in plain degrees, you realise it's actually totally trivial and obvious. All the confusion comes from trying to understand the standard receiver instrument.