How to rotate game object on fixed position

Hi can anybody please tell me that how to make game object rotate on fixed position! Please
tell me the full procedure with steps as i’m beginner to unity.

You should use transform.Rotate - this rotates the object without modifying its position. If you want the object to spin continuously around the Y world axis, for instance (script attached to the rotating object):

var rotSpeed: float = 60; // degrees per second

function Update(){
  transform.Rotate(0, rotSpeed * Time.deltaTime, 0, Space.World);
}