Step three: Satori When Samadhi goes deeper, there starts an upward flow of energy with a huge force as if a whirlpool of energy is formed; the union of Samadhi and energy at its peak is termed as Satori. It is almost like a glimpse of enlightenment.
You can understand it in this way - like we are going towards the peak of a mountain through ghats. Due to the roundness of the road we have started seeing the peak from a distance. Moving on the road, a certain point will come where from the topmost point of the peak is visible. Then again moving further may be that point is not visible ... Hence, Satori is the glimpse of that peak of Enlightenment.
Step four: Enlightenment When the event of Satori takes place it means you are close to the destination of Enlightenment. But that too disappears, and then too the journey still remains. The route is route, you need to move on in some more circular rounds, but at the end one will reach the goal of enlightenment. Reaching to that peak is Sambodhi, enlightenment or in the language of Patanjali it is Nirvikalp Samadhi. Now that state of disappearance of duality is not momentary but permanent. Now there is no returning back; that peak has become the abode - this is called Enlightenment.
I would like to emphasize - each and every person can dive in oneself; starting from witnessing, traveling through Samadhi and Satori and reaching the peak of Enlightenment.