In chapter 2 of the novel, during a meeting of the boys, Piggy becomes frustrated that the group is unable to make a proper signal fire. He is also frustrated that the other boys don't seem to be taking their situation on the island very seriously. They have after all been stranded on this unfamiliar, uninhabited island without any adults to take care of them and with little obvious prospect of being rescued.
When the boys' only response to the unsuccessful signal fire is to break out in fits of giggles, Piggy has enough and exclaims, "How can you expect to be rescued if you don't put things first and act proper?" This is of course a rhetorical question. The answer, which is that they can't expect to be rescued if they don't "act proper," is implied by the question itself.
Piggy tells the boys that they should be making shelters for themselves and that they should listen more to their elected leader, Ralph. He chastises the other boys for not even knowing how many "little 'uns" there are in the group. Piggy points out, ominously, that one of the "little 'uns" hasn't been seen for a while.
This is perhaps the first moment in the novel when the boys, thanks largely to Piggy, realize the seriousness of their situation and the corresponding need for proper organization. In this moment, Piggy also establishes himself as the voice of reason among the boys. Unfortunately, as the novel progresses, Piggy's voice of reason is increasingly overwhelmed and drowned out by the primitive, instinctive, irrational impulses of the other boys.