Have you ever tried to assemble a stereo system, bicycle, desk, or any other device? If so, you know the importance of clear and complete instructions. Just one vague phrase or missing step can make the job very difficult or even impossible.

Explaining to a reader how to do something is a form of process writing. If the goal is to teach the reader how to duplicate the process, it is called directional process writing.

If the writer doesn't expect the reader to carry out the steps involved, she or he uses an informational writing pattern that offers a general overview of the process.