NPC and player dialogue?

So I know how to add NPC dialogue and stuff, but I want the player talking to the NPC to actually have a conversation with him. For example, I want a runescape tutorial guide to say "Welcome to Runescape" or something like that, then I want the player to say "Who the hell are you?". But I don't know how to make the player dialouge work.

So I can make the NPC talk:

Code:

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                case 2253:
                        p.frames.showChatboxInterface(p, 242);
                        p.frames.animateInterfaceId(p, 9827, 242, 2);
                        p.frames.setNPCId(p, 2253, 242, 2);
                        p.frames.setString(p, "Wise Old Man", 242, 3);
                        p.frames.setString(p, "Hey there "+ Misc.capitalize(p.username) +", welcome", 242, 4);
                        p.frames.setString(p, "to Runescape", 242, 5);
                        break;

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But how do I make my player respond back "Who the hell are you?"?

Please help?