VOR systems work by sending a highly directional signal using a phased antenna array from a station located on the ground. This signal rotates clockwise horizontally at a speed of 30 spins per second.
Simultaneously, a 30 Hz reference signal is emitted on a subcarrier. This is timed so that the signals are in phase as the subcarrier crosses magnetic north. This line of position is the radial of the VOR.
A VOR station has 360 different radials, each of which can be flown in 2 different directions. They all run through the center of the station before exiting. Each radial has an alignment with a certain compass degree - 0 degrees points North, 90 degrees points East, and 270 degrees points East.
The point at which the radials of 2 separate VOR ground stations intersect is used to fix the position of the aircraft in the sky. This is similar to how RDF (radio direction finding) systems operate.
To figure out which radial you are on, you will first need to tune into the signal and identify the station it is coming from. Turn the OBS until the needle has been centered and you see a FROM indicator. Look at the top of the display for a number - this is the radial that you are on.