Can someone pls explain the poem 'Nothing Gold Can Stay' line by line?

The line 'So Eden sank to grief' is an allusion, or literary reference, to the Biblical story about The Garden of Eden, a perfect paradise until Eve ate from the Tree of Knowledge. By making this reference, Frost is implying that the idea nothing good can last is an old one; it's part of our human experience.

they would have to clean it very clean

if you have to come up with one i would do

love: happiness