According to the 'Sai-Nana dialogue' in the text, what is the prescribed method for attaining true knowledge from a Guru?

In the 'Sai-Nana dialogue' described in Chapter 39, Nana Chandorkar explains the traditional path to gaining spiritual knowledge from a Guru. Based on a verse from the Gita, he states that one must approach a Guru with great humility. This involves three key actions: prostrating at the Guru's feet, serving the Guru with one's life, and asking respectful questions. Nana explains that by following this path of devotion and sincere inquiry, the Wise ones who have perceived the Truth will then graciously impart their knowledge to the seeker. This method is presented as the Lord's own instruction for spiritual learning.