Hi, and welcome
I found your question very interesting. One would assume that the exercise requires you to do something entirely contradictive. However, there is a point, namely to make you develop argumentative skills.
It requires you to:
1) Realize what's the (fictional) story you've written really about, and thus it also offers you the chance to criticize your writing more objectively.
2) Develop a way to build the structure logically and coherently.
More specifically, regarding the story you offered us:
1: Think what is Keong's reality. Consider the settings, his frame of mind, etc.
2: In this reality, what is the story describing in particular
3: Which are the decisive events taking place and how do they affect the character.
I'm offering you now some very generalized quidelines/examples of how your essay should be structured, but you can experiment with it yourself and add/alter details.
An essay must have a thesis statement. That is, you must mention, early on, the purpose of this essay (i.e. what are you writing about).
You could begin with a general note on how war alters the mentality of people and then move into more directly related details of your story. The thesis could be something like "This essay offers a description of the last days of a war, seen through Keong, a young man whose life was interrupted by this war. The focus is on the thoughts and emotional responses of war participants such as Keong."
Then go ahead, into the main "body" of the essay, where you could describe e.g. environment vs. emotions (that is, how the surroundings--land mines, war, death--make Keong feel). Develop that, in a way that creates connections between event and emotional response. Later on, you can focus on how Keong's emotions are altered by the war coming to an end.
Ending the essay, you can offer a short list of the events you mentioned and how they affected Keong. Then you could generalize, making it not only Keong's story, but a story for every young man in a similar situation.
Tips
Regarding fiction vs essay, consider these:
1) In essays, avoid any emotional sentences of your own. Don't say
A hot wind whipped mercilessly across his dirt streaked face, knocking him back to the present. Instead, say N
evertheless, regardless of a soldier's desire to disassociate himself from reality, the environmental manifestations, such as extreme heat or cold, always remind him of where he is.
2) As you saw above, use formal words and expressions. Not
break away, but
seperate/disassociate. Avoid phrasal verbs: don't use T
he soldier went for him; say
the soldier attacked him
3) Keep in mind: you're not writing a fiction story anymore, you're writing an essay. That means, you treat the fiction story as a piece of
realistic writing, which you use as a "source" to write a report, an essay about the core elements that it represents.
Good luck
