How was the author of the Sai Satcharita supposed to write the book? Did Sai Baba give him any specific instructions or promises?

Yes, Sai Baba provided very specific instructions and profound promises regarding the writing of his life story. As detailed in Chapter 2, Baba told the author that he was 'merely a pretext' and that Baba himself would 'write my own story.' The main condition was for the author to 'dissolve his ego and surrender it at my feet.' In return for this surrender, Baba made a powerful promise: 'To one who acts thus in life, I give full assistance. Not just this story, but I shall serve in all ways in his home.' This indicates that divine help was contingent on the author's complete humility and self-surrender.