A plane is a flat surface that extends infinitely in all directions; thus, a lot of points can be found on a given plane. The plane can be named by taking any three points on it, in no specific order, as long as these points are not on a straight line. An example is plane ABC, given that points A, B and C are found on the plane and are not collinear. So you name it whatever is on the plane...hope this helps.
