Piggy sensibly realizes that, before the boys even think of making a fire, they need to start building shelters down on the beach. Piggy understands that, if the boys are to be rescued, they need to get their priorities right. Unfortunately, Piggy's sensible advice is ignored by most of the other boys, who can't wait to go screaming up the mountain and get a good fire going. In their over-excitement, they build a fire that rapidly gets out of control and uses up all of their existing supply of wood.
The boys have only been on the island for a little while at this point, but already the tensions that will develop among them are starting to emerge. Specifically, we see that the rules-based order that Piggy and Ralph want to establish on the island is under serious threat from the immaturity of the other boys.