Okay , i need understanding the instructions on my quiz for english. i'm not asking for answers but what the heck is my teacher talking about.

"most style guides are organized in similar fashion, with a directory of common models to consult as you create a references list. understanding how to use this directory is crucial to being able to create a references list in the correct style. the first point to understand is that the directory of models is organized according to the category of source (book, periodical, so you must first decide which category to look in, and then look for the best model to follow in that category. that said, sometimes you will have to combine information from two or more models to get the correct citation.

examine the directory of models in chapter 7. then, choose and follow the example that matches your source the closest."

"quiz question information: there are seven short answer questions. each question presents reference material information. you will create a properly formatted reference entry for the given reference material information. this situation is somewhat artificial, in that, if you had done the actual research, you would know what category of source you had (book, periodical, however, for the purposes of the exercise, the categories of sources are labeled and provide additional information."

what is he asking me to do?
what is a directory of models?
periodical?

again i am not asking for answer to my quiz but i'm asking for someone to explain to me what am i doing exactly,. what is he asking me to do?