What I mean when I refer to a "reading" of a text is really an _interpretation_ of that text, or a particular _way_ of looking at it. In other words--to take our example from class--let's say your textual detail is Nat's cigarettes. And let's say that the "critical idea" you decide to focus on from the Bressler reading is this line from p. 225: "...Cultural Poetics avoids sweeping generalizations and seeks out the seemingly insignificant details and manifestations of culture frequently ignored by most historians or literary critics. The anthropologist Clifford Geertz describes these seemingly insignificant details as anecdotes that are "quoted raw," a note in a bottle."

SO the subject of your paragraph is how you might apply this idea to the seemingly trivial details involving the cigarette in order to arrive at an interesting interpretation of the story. If you were to study the history of cigarettes in World War II, this might provide you with an "anecdate"--a historical "note in a bottle"--that might allow you to say something about Nat's character and what he represents. This might lead you to see the story as a sort of comment on the war itself, or on politics more generally, or on England's place in the world. The fact that he smokes the last one at the end of the story might, in the course of your research, take on a kind of symbolic weight that would encourage you to understand the end of the story in a very particular way, and this might then shape hw you read the story, or what you think it is essentially saying to us.

In other words, your job is to spin out how you might approach your detail in light of the idea or concept you choose. You aren't being asked to actually _do_ the research that would be necessary to offer an original interpretation of the story--just to think about how the juxtaposition of a textual detail and a critical idea might get you there.