For a poem about death, this one sure is noisy. Mostly, those noises are there to remind us of the human grief that surrounds death, but they're also the death knell itself—a sound to remind the speaker that it's time to go.
Line 2: The "sunset and evening star" act like a "call" for the speaker to make his final journey from life to death. The call probably isn't literal; it seems to be a metaphor for the speaker's belief that death is headed his way.
Line 3: The bar can't actually moan or anything, so this is an example of personification, the attribution of human qualities to non-human things. But it's also a moment in which the land itself—this sandbar—seems to be mourning for the speaker. That mourning is reflected in the sound it makes, which is really nothing more than the sound of water flowing up over the bar.
Line 6: The speaker hopes for a tide that is "too full for sound and foam," meaning he'd like to pass quietly out into the open ocean, without much ado. No crashing of the waves, please and thank you.
Line 9: At twilight, there's an "evening bell." The bell reminds us of the death knell—a traditional ringing of a bell to signal that a person has passed on.