Based on the preface, how can followers use literature to serve their Guru and the community?

As detailed in Chapter 0, followers can serve their Guru and the wider community by creating and engaging with spiritual literature. One significant act of service is for a devotee to write a detailed prose or poetic biography of their Guru. The Sadguru accepts this service through the book. This service extends to the community, as when other devotees study and perform Parayans of the biography, the author gains the merit of serving 'God in humanity' (Jan-Janardan) and performing public service. This process allows the entire congregation of devotees to achieve the purpose of their lives through the shared study of the Guru's life.