This question has been asked due to 100 Years of 1919 act. The Act of 1919 (also called Montague Chelmsford Reforms) has many contributions towards constitutional development of India. The introduction should explain in general about the GoI Act 1919 with mentioning some of its contributions.
Further, the main body should contain the main features of Montague Chelmsford reforms.
Next, mention about Montague Chelmsford Reforms and administrative devolution. Like it introduced parliamentary system in India, involvement in budget making and policy formulation, participation in central legislative assembly, diarchy i.e. decentralised form of govt, elections to legislatures, separate provincial subjects, separate budget, Indians into administration etc. and bring conclusion on the basis of it.