He opens the the window and the raven flies in. He ignores him and perches himself on a statue of Pallas Athena (which is the goddess of wisdom)
you will just leave in the morning
He looks at the raven and it makes him smile. The bird looks serious and that's what makes him smile. He asks the raven what its name is and the raven replies "nevermore."
the raven probably only knows the word nevermore
He is surprised the raven answered him. He recognizes that this is an unusual thing.
what does nevermore mean?
He thinks this is something really important since the raven is talking to him. He is also thinking that the raven will just leave in the morning, just like his wife did. The raven answered "nevermore" again. The raven is saying that he will never leave. The narrator has lost his hope.
The narrator realizes that the raven only knows one word, which is nevermore. He thinks that this is the only word the raven's master taught him. The narrator also thinks that the raven must have escaped from his master, who was probably sad.
The narrator moves his chair inferno of the raven. He stares at the raven and tries to figure out what the word nevermore means.