I know it, by the numb look Such Houses have — alway — (3-4)
What kind of look do houses normally have? What are the signs of life? How could a house look numb after a death within it? The speaker says he could tell there was a death just by looking at the front of a house, that he'd seen that kind of thing before, in fact, "alway." Is this a case of projection? Does the speaker himself feel numb and therefore see it in this house? It's clearly a case of personification, where the poet gives the house human feelings and reactions.
A Window opens like a Pod — Abrupt — mechanically — (7-8)
Last time we checked, windows don't just open by themselves. Here one does, "like a Pod." This is the first of this poem's only two similes. The house is acting on its own, naturally, quickly, mechanically. It's like the house is on autopilot. Things just happen on their own. At least that's how it appears to the observer seated at his window.
The Minister — goes stiffly in — As if the House were His — And He owned all the Mourners — now — (13-15)
Every "as if" pulls on a rope the fact pulls the opposite way. "As if" acknowledges there's the true "really is." Is this house the minister's? Well, no, but he's acting as if it is. Does he own the mourners now? Take it up with him.
It's easy as a Sign — The Intuition of the News — In just a Country Town — (22-24)
Leave it to Dickinson to act like she's giving us a kind of moral at the end of her list of death's attendants, but making it a riddle instead. She says it's easy, but is any of her poetry ever completely easy? A lot of the meaning of these lines lives in the word "Intuition." You should know that Dickinson created her own kind of dictionary of terms that meant something to her and her alone. Here's one of her definitions: "By intuition, Mightiest Things Assert themselves -- and not by terms—" (source). This inner perceptiveness is crucial to a poet, one who lives through observation. It's interesting to see that she attributes this capacity to the whole town.