The mysterious narrator says that the first thing it sees is "the colors" (1.1), and next it sees the "humans" (1.2).
Now the narrator is telling us we "are going to die" (1.6), but that we shouldn't "be afraid" (1.7) because the narrator is "fair" (1.8).
We will all meet the narrator at some point – it will take our souls in its arms and take us "gently away" (1.12).
(In case you haven't figured it out yet, the narrator of The Book Thief is Death. We refer to death as "it" because we don't yet know if Death has a gender. (Though we find out near the end of the book.)
Death wonders what color the sky will be when it comes for you.
See, Death's favorite is a nice "chocolate-colored sky" (1.15) but all the colors give Death pleasure.
There are "A billion or so flavors" of colored sky; they each taste different to Death. Sucking on colored sky is stress-relief for Death, who has lots of stress.
Death needs this "distraction" to say "sane." (1.14). But what Death really needs is a vacation. Sadly there's nobody to replace it.
Death says that the reason it needs a distraction is because it's really painful to watch the people who are "leftover" (1.22), the ones who don't die when their loved ones do, the ones who stay behind with broken hearts – "The survivors" (1.24).
Death is about to tell us a story about one such survivor.
At the end of this chapter, Death says that it "saw the book thief three times" (1.31).