What are steps involved in buidling and CI application?

[eluser]Unknown[/eluser]
Hi people, sorry for asking an weird question

My question is about steps before coding. I mean if we want to build an CI app, normally how should we start (knowing our requirements)? How do we brainstorm? After brainstormed, where should we start coding at, i.e. View, or Controller? etc.

Thanks for your help! I really appreciate it.