Starts out with the day about to be over. It is time for bed. A "mother" is leading her child to bed. The mother is being compared to nature (mother nature).
The child kind of wants to go to bed but is also being stubborn about it. He wants to stay awake.
The child leave all the broken toys on the ground. And as he is leaving them he is still looking back at them through the door that is still open.
While the child is still being lead away from his toys and he is worried that there won't be any new toys wherever his is going. But if there are new toys the for child, that would be awesome and that would make him very happy
So nature takes us away from our life, leads us away from our toys from our old life, and take us by the hand to lead us to rest
And she does it so gently that we go, but scarce about weather we should stay here or leave. We are too tired to think about how deep the unknown before us goes.
Almost the whole first half of the poem is a whole metaphor. Longfellow is talking about a mother and her child, but really the mother is a figure for mother nature and the child is like a human.
There is a lot of visual imagery in the poem as well. for example; "leave his broken playthings on the floor", "leads by the hand her little child to bed" leave a good visual image in your head.
The second half of the poem it reveals to us that nature is actually the mother of us. "So nature deals with us, and takes away our playthings one by one, and by the hand leads us to rest so gently". Talking about how one day nature will come through and one day take us away from our life and we will die, but thats okay because thats the way its supposed to be and we will go peacefully.