This is the very basic introduction to pendulum dowsing. The first thing we need to know is how to hold the pendulum. There are different ways of holding it, but the most common is to hold the string either between the thumb, the index and the middle finger of the dominant hand or just the thumb and index finger. The most comfortable length of the string (or chain) is between 1-3 inches. Any shorter - and you may sacrify the accuracy, any longer and may wait forever for the movement.
I put the end of the string inside the palm of my hand, position my wrist so that my fingers are in line with the string.
You start by asking what your "yes" answer movement is. If your pendulum doesn't move at all - chances are you control its movement too much. You can even slightly push it to give it a starting motion.
By the way - you don't ask your pendulum, you ask your subconscious mind.
In my case the "yes" answer movement is a clockwise rotation, but yours could be different, for example back and forth, and that is fine as everybody is different.
Now you ask to see the movement for the "no" answer. In my case it is a counter-clockwise rotation and again - yours could be different.
Those are the two basic movements that you need to learn to start dowsing with a pendulum.