I would spend the first paragraph introducing the story just a little, mentioning that it focuses quite a bit on greed, and then at the end of the first paragraph, writing what I call a "theme statement" about greed. For example, "In this story, Lawrence shows how greed is a dangerous force in people's lives." That will be the thesis statement that guides the rest of your paper.
Then, in the next four paragraphs, structure it as follows. 1. A topic sentence where you state something like, "One instance of greed being destructive in the story is..." and then, 2. List the example and explain it. Then, 3., discuss how that example is showing greed's dangers. Follow that formula for all of the paragraphs. I'll include a sample below, to show how that will look:
One instance of greed being destructive in the story is when Lawrence describes how the mother of the family cares more about materialistic matters than for her own children. In the beginning of the story, it states that "she could not love" her children, and yet was obsessed with luck and earning more money. Her lack of love drives her son to gain money, which leads to his death. This obsession with greed is one way that it is dangerous in the story.
That paragraph above is a sample of how you might write the 4 body paragraphs. Then, in your conclusion paragraph, just summarize your main points, restate your thesis sentence (the theme statement from the first paragraph), and wrap it up. I hope that those thoughts help you to get started! Good luck!