If what you are looking for is just the words spoken between the Naval officer and Ralph at the end of the story, here it is, whithout the explanatory passages:
“Are there any adults—any grown-ups with you?”
“Fun and games,” said the officer.
“We saw your smoke. What have you been doing? Having a war or something?”
“Nobody killed, I hope? Any dead bodies?”
“Only two. And they’ve gone.”
“We’ll take you off. How many of you are there”
“Who’s boss here?”
“I am,” said Ralph loudly.
“We saw your smoke. And you don’t know how many of you there are?”
“I should have thought,”
“I should have thought that a pack of British boys—you’re all
British, aren’t you?—would have been able to put up a better show than that—I mean—”
“It was like that at first,” said Ralph, “before things—”
“We were together then—”
The officer nodded helpfully.
“I know. Jolly good show. Like the Coral Island.”
It's very ironic, when read like this way, almost funny from a certain point of view. Here we have an island of boys that tragically and starkly mirrors the world of men, and the representative of the men talks to the representative of the boys. Both groups have been at war. The man, the Naval officer, doesn't quite get it, though. He sees it all as boys at some kind of play that ended in badly. He figures they could have done better. Ralph sees it for what it is: boys being what boys are, just small men, doing what all men eventually wind up doing. For Ralph and all the boys, it was no game, and they tried, oh they tried, but they couldn't have done any better.