First, you may be asking, “What is a writing model?” A writing model is an example of writing like the one you need to produce.
Allow me to illustrate. Very early in my graduate program, I had never read a dissertation. But I knew I needed to write one. The best advice I received was to familiarize myself with the structure of a finished dissertation. I found dissertations that students in my own program had successfully written and defended under the guidance of my advisor.