The first step was gathering preliminary information in order to create a project plan. After I had properly scoped the project, I was able to begin to gather additional information from the Program Manager and Software Engineers.
To write the frontend docs, I acquired multiple mobile devices and checked the descriptive docs against all the interface elements and all procedural docs against all the mobile phone functionality.
Finally, to write the backend docs, I carefully described the API of a Software Porting Kit, focusing on XML content contained in SOAP messages, including requests, responses, headers, and the message body. Ultimately, the document contained an overview of the underpinnings of a Microsoft core protocol: its protocol data unit, bindings, and transport methods.