Attributes of Krishna: Krishna - The Cause of All Causes

Q. In Bhagavad-Gita 2.47, Lord Krishna says, "You have the right to perform your prescribed duty, but you are not entitled to the fruits of action. Never consider yourself the cause of the results of your activities, and never be attached to not doing your duty."

Question a) In this world activities are performed with the results in mind and in fact the results are the motivation for one to do work. How does one perform his
activities in this world without expectation of fruits / results?