"To His Coy Mistress"

In Andrew Marvell’s poem “To His Coy Mistress,” I was kind of confused. I re-read the poem a couple times, but it seemed when I thought I understood the poem, I would re-read to check and get confused all over again. Maybe I have been trying too hard to understand the poem. The lines, “To walk, and pass our long love’s day./ Thou by the Indian Ganges’ side.” (Lines 4-5) was kind of confusing to me. I didn’t really understand it that well. I am also confused at the end of the poem. “Thus, though we cannot make our sun/ Stand still, yet we will make him run.” (45-46) “Thy beauty shall no more be found,/ Nor in thy marble vault shall sound” (25-26) seems to me that someone dies because when I read the “marble vault” I thought of a casket, which is sometimes can be made of marble and acts like a vault. But then when I re-read the poem and got to that part I think I misinterpreted the meaning.