How does one approach serving a Guru to gain knowledge, as described by Dnyaneshwar Maharaj?

According to the commentary on the Shrimad Bhagavad Gita by Lord Samarth Sadguru Dnyaneshwar Maharaj, the path to gaining knowledge involves dedicated service to the saints. As cited in Chapter 0, one should "serve the saints with your entire being." This process involves surrendering with your body, mind, and soul at their feet and performing all service without ego. The text suggests that service is the very doorway to the treasure of knowledge. By following this method of selfless service, the saints will then impart what you have asked for, leading to an enlightened heart where doubts no longer arise.