What are some established methods for devotees to engage with a Sadguru's teachings and serve him, particularly through written works?

A Sadguru accepts service from devotees in two main ways through books. Firstly, the Sadguru may create great works themselves, like Shri Dnyaneshwari. Secondly, and relevant to community building, the Sadguru has biographies written by devotees. As detailed in Chapter 0, devotees can then perform service by studying these biographies and conducting Parayans or Saptahs. This act of study not only serves the Guru but also allows the writer to gain merit for serving God in humanity, fostering a community of practice among all participants.