In The Tell Tale Heart, the narrator creeps up on this old man. He then kills him because he is vexed by the old man's large and annoying looking eye. This is the climax because it is a major turning point in the story.
In the Tell Tale Heart, the narrator sneaks up on the old man in his room at 12:00 every single night. He also stares and observes the man very closely at every action. This is again and again because he creeps up on the old man again and again.
Towards the end of the Tell Tale Heart, three police show up at the dead old man's house to search around. This is a falling action in the story because it happens at the end of the story and brings a bit of a twist.