Long exposure photography means that "long exposure" is the name of the technique in which the camera's shutter is open on left and shoots a trail of light or object during a period of time.
Settings and how to shoot it - The shutter should be open till 20 seconds and a little light goes on the subject so it can be visible.
Used a stand to keep the subject on a high level and used a light. Fixed it on the hand of the subject and tried several times then found the mistake. Thought about how to overcome it and finally clicked this shot.