What role does the first couplet of the poem "Looking Alone in the Border Town" play in the whole poem? Please come in and analyze.

(1)① Start with the topic and point out the time and place (1). ② Words like "carefree", "lonely" and "full autumn" begin with a lonely and desolate atmosphere (1). (3) It echoes the "desolation of the motherland" and "Who asked" in the couplet (1).

(2) Modify "Twilight Blowing" and "Leng Yun" with "Whispering" and "Sadness", vividly describe the bleak night wind and Leng Yun, and also write the author's mood; "Jing" not only describes the scene of "red leaves" falling in the autumn wind, but also writes the "Jing" in the poet's heart by personification. "Pressure" not only vividly describes the weight of Leng Yun, but also shows the poet's heavy mood (just enjoy "rustling", "misery", "shock" and "pressure" in any two places, and get 1 for one question correctly, and 3 for two questions correctly).