How to write a project support manual?

Question

Frontend

It became such a task to write a small instruction on supporting the current project (website) for developers. In order not to suddenly build a bicycle, Maybe someone has ready-made options or maybe someone knows where it is possible to find examples of how such an instruction is drawn up?

Answer 1

Letters. There are no standards here

Answer 2

You sit down and write.

Answer 3

1. A block diagram with blocks and a description for each of them (API for internal integration, description of classes, description of all interfaces and types of processed data).
2. Give 2-3 examples of actions to expand a specific functionality with synchronous and asynchronous processing of the necessary operations to implement the desired extended functionality.