Sometimes you analyze the author's mode of expression: Why is this choppy? All of your analytical passages combine to support your essay's thesis. It is not necessary to imitate the chronology of the literary work you are analyzing.
Since both you and your reader have completed a reading of the literature you are discussing, you can draw upon examples from all sections of the text in whatever order best suits your argument. When writing about a novel, a story, or a play, remember that your reader already knows the plot.
E.g., you might choose to write about distortions of biblical narrative in Chaucer's "Wife of Bath's Prologue." Somewhere within your first paragraph you want to include a sentence or two that describes your thesis.
A thesis is your assertion about your topic, a statement that indicates to your reader what the direction of the argument in your essay will be.
E.g., rather than telling your reader that Celie is raped by her stepfather in Alice Walker's The Color Purple, you might claim, "When Celie is raped by her stepfather, she describes her pain and confusion in fragmented sentences and innocently crude language." From there you would provide textual examples, and comment upon each one you select. In literature, secondary sources are usually critical essays and books that have been published on the primary, literary work you are reading.
When your professor tells you that you do not need to use secondary sources to write your essay, he means that he wants to read your interpretation alone.
You gain authority through the originality, thoroughness, and intelligence of your analysis. Most people have had the experience of being personally moved by a literary work.
Kate Chopin's novel, The Awakening, or James Baldwin's novel, Go Tell it on the Mountain, might parallel a self-discovery experience you have had.
Make sure you discuss the poem, not simply the friend John Keats seems to be describing; analyze the force of John Donne's imagery rather than the religious experience you have had. It is as impossible to prescribe a formula for the opening line of a literary essay as it is to tell a poet or novelist what the first line of her literary work should be.
If you believe that your purpose is simply to satisfy an assignment that scarcely interests you, feel free to start your essay with a sentence that will allow your reader to share your boredom.