The first two chapters of And Then There Were None contain a great deal of foreshadowing, relating to future plot events of the story (and even, perhaps, to the identity of the killer).
As the story opens, we are introduced to the various guests, beginning with Justice Wargrave, then Vera, and so on. What's interesting about this first chapter is that we already are beginning to see the degree to which many of these characters are in some way haunted by their past. Vera's mind flashes back towards the scene of Cyril's drowning (chapter 1, part 2); Lombard, meanwhile, recalls that in his past, "legality had not always been a sine qua non" (chapter 1, part 3); Macarthur complains about the effect of a rumor, connected to an event three decades earlier (chapter 1, part 5), etc. So many of these characters are haunted in some way or another. However, Wargrave shows no guilt or regret whatsoever regarding his past, which is a detail that foreshadows his role as the murderer.
In addition, you might also notice the last two lines which close the book's first chapter:
"He's nearer the day of judgment than I am!"
But there, as it happens, he was wrong.
These two lines allude to future events in the story, suggesting that Blore will be killed somehow later in the story.
The second chapter continues much of the same character-based foreshadowing that is so critical to the first chapter. It is in the second chapter, for example, that we learn of Wargrave's reputation as a hanging judge. (This will be a deeply important point of the book, being that it is both the grounds on which Wargrave is accused during the "indictment scene," even as this detail is also closely tied into the motivations that drive Wargrave to kill in the first place.) Additionally, in the second chapter, we are introduced to the poem "The Ten Little Indians," which will be a major plot point for the rest of the novel, shaping the methods by which Wargrave kills his victims.