How did Sai Baba guide his devotees from Saguna (with form) to Nirguna (formless) realization, based on the teachings in Chapter 11?

Chapter 11 of the Shri Sai Satcharitra describes the various methods Sai Baba used to help his devotees transition from worshiping his physical, Saguna form to realizing the formless, Nirguna reality. The text mentions that Baba employed countless means tailored to each devotee's eligibility. For example, he would send some to other countries, confine others to solitude in Shirdi, lock some in the Wada, or assign them the task of reading scriptures. By practicing these disciplines for years, a devotee's mind would become constantly occupied with Baba's essence, leading to a growing longing for the Nirguna even while engaged in worldly activities. This was his way of preparing them to focus on the eternal aspect beyond his perishable physical body.