Jack has a penchant for leadership from the beginning. As choirmaster, he is in charge of the choir from the beginning. He tries to gain control of the entire group, but Ralph is able to talk the others into it due to his finding the conch.
Jack likes making rules and making others follow them, but he has no real interest in being a leader. He just wants to be in charge and make others do what he wants them to do.
Jack is described as a “practiced debater” one of those who “would use their whole art to twist the meeting” (ch 5). During the meeting, Jack repeatedly tries to talk and finally is able to get the conch away from Ralph. He insists that the littleuns are just having nightmares and there is no beast on the island, and nothing to fear.
Jack violently grabs a boy named Percival and asks him where the beast lives. He is trying to turn everyone against Jack by convincing them that there is no beast. He draws upon his experience as a hunter. He becomes “unaccountably angry” at Piggy when he takes the conch. He vocally contradicts Ralph’s leadership.
“And you shut up! Who are you, anyway? Sitting there telling people what to do. You can’t hunt, you can’t sing—” (ch 4)
The society of the boys is breaking down, and Jack’s arrogance and bullying is a large reason for that. He questions Ralph’s authority, and picks fights with Piggy, who is the only intelligent kid there. This is the beginning of the end for what little structure and civilization the boys have.