Acharya Prashant explains the Kena Upanishad, starting with the meaning of the word 'Kena,' which translates to 'by whom' or 'by what.' He emphasizes that the Upanishad begins with a fundamental question, asserting that without intense curiosity and the urge to know, the Upanishad cannot manifest. He describes the Upanishad as a process that occurs when a student is truly ready and a teacher appears. The speaker highlights that the questions posed in this scripture are sharp, pointed, and essential, reflecting a deep-seated eagerness to understand the source of the mind, life, and the senses.