@zee_dad_khan - This is to test your fuel pump pressure. Your car has an electric fuel pump, when you bring the key to the 'on' position, the fuel pump is activated and the fuel sent to the fuel injectors.
Leave the key in 'on' position for about 4-5 seconds and try to start. If you see it starting correctly using this procedure then the issue is with your fueling system.
Have your mechanic check the fuel pressure before and after the fuel filter. If the fuel pressure is low before the fuel filter, then you likely have a bad fuel pump. If it is low ONLY after the fuel filter, replace your fuel filter. If the fuel pressure is fine on both ends, have your injectors cleaned and tested.