How does Jack interact with others in chapter 2?

In chapter 2 of Lord of the Flies, Jack's true domineering nature starts to emerge, along with all his arrogance and desire for control. Piggy and Ralph are making strenuous efforts to establish a rules-based system of order, but Jack is not remotely interested. It's obvious from his actions that he wants to be in sole charge of the other boys. From the start, he actively tries to undermine Ralph's authority by interrupting his speech and unilaterally declaring himself head of the hunters. Most of the boys follow Jack, which provides an eerie foreshadowing of how things will eventually turn out. For Jack, violence and control are what really matters, not silly little rules that can hold him back in his quest for power. His insistence that the conch doesn't matter on top of the mountain—his preferred domain—indicates his total contempt for any kind of civilized society on the island.
At this stage of the story Jack is disrespectful to Ralph, but he's physically and verbally abusive towards Piggy. He forcibly removes Piggy's glasses to use them to start a fire. The fact that Piggy is practically blind without them doesn't concern Jack in the slightest. Piggy is the voice of reason on the island; it's not surprising that Jack can't stand him. Although Jack can easily intimidate and dominate Piggy, he knows that so long as he's around he can never have the total control he so desperately craves. Piggy is an obstacle to his plans for domination, and Jack hates him for it. Unpleasant as Jack's behavior is towards Piggy at this point, it's a mere foretaste of what's to come.