Because the question specifies that the assignment involves the writing of a magazine article, as opposed to a research paper, the methodology is relatively simple.
A research paper is, by definition, the product of scholarship. What this means is that the student or scholar conducts research, which could involve interviews with individuals who participated in an event being described, or actually going out into the field to observe first-hand some kind of event or phenomenon, and then citing that source of information in footnotes or endnotes (footnotes tell the reader what the source of the information is and where that information can be located, and is placed at the bottom of the page; endnotes serve the same purpose, but appear in a section at the end of a chapter or at the end of the report or book).
Magazine articles are not research papers, although the same type of research may be involved, and often is. Articles, whether in magazines or newspapers, do not use footnotes or endnotes. Instead, the source of the information is directly identified in the text of the article. For example, an article might read as follows:
'Bob and Jim were discussing whether to jump into the ocean and try to retrieve the box, according to Jim.'
The source of the information is presented alongside the information the source provided. In articles discussing a serious matter involving sources of information who do not wish to be identified out of fear for their physical safety or out of concern they will lose their jobs if identified in the article, the journalist or author will specify that information:
'According to a witness to the event, who does not wish to be identified because of threats to his life, Jim and Bob together beat the victim with baseball bats.'
This is how magazine articles are written with references to sources. When a teacher or instuctor wishes the article to be accompanied by a list of sources, then a bibliography has to be constructed. This is a simple matter of listing, one by one, the sources of information used in researching the article, possibly with added notations indicating which source provided which information.