In the exposition, the narrator (antagonist) elaborates to us on how he is not "mad", and that he is nervous. However, he can tell the story very calmly. The narrator telling us that he is nervous, although he tells the story very calmly he is just proving to us that he is a very unreliable narrator. Also, the narrator has a strong urge to kill the old man over his "vulture eye".
I can't tolerate this sound , go away, go away.
The rising action starts with the narrator telling us how he is not mad, because he is so wise how he proceeded with caution, the narrator says he was very kind to the old man during the whole week before he killed him. At the dead hour of the night, midnight (foreshadowing) the narrator would look in on the old man, he would open the lantern every night as well, to see if the eye was open or not. The narrator asks the old man how he slept to see if he expects anything. Personification is used when the narrator personifies death, when he says "death, in approaching him had stalked with his black shadow before him, and enveloped the victim".
"I cut off the head and the arms and the legs".
On the eighth night, the narrator accidentally wakes up the old man, because the narrator's thumb slipped on the lantern, which woke up the old man. The old man and the narrator have a one-hour standoff in the room, the narrator does not move a muscle. However, the old man sits up in the bed listening. After an hour passes, the narrator opens a small crevice in the lantern and a ray of light shines right on the old man's eye. The narrator begins to hear a low, dull, quick sound and thinks it is the old man's heartbeat getting louder, louder, and louder. The narrator believes that the sound would be heard by the neighbors.
"dissemble no more! I admit the deed."
The climax is when the narrator finally finds the urge to kill the old man. The narrator could not tolerate the beating sound, and then just suffocated the old man with his mattress.
In the falling action, the narrator dismembers the corpse in the bathtub so when he cuts up the body there will be no blood remaining. The narrator hides the body parts under the floorboards. Later, the police arrive at four o'clock requesting to search the premises. The police were sent because a neighbor heard a shriek. The narrator ends up being overconfident and puts his chair right over the floorboard where the corpse had been dismembered. The narrator begins to hear the "old mans heartbeat", getting louder, louder, and louder, then finally, he flips out.
In the resolution, the narrator confesses to the murder of the old man to the police. The reason why the narrator admitted to the crime was that he could not stand the sound of the old man's heartbeat, which symbolizes the narrator's guilt (internal conflict).