How to make a dialog appear when you talk to an npc + how to push e to talk to them?

I've been trying to find out how to make a dialog appear when an npc speaks to you. And how to script e to interact with npcs that can talk. Here an example of what i'm saying: Pretend you walk up to an npc and push e on them (witch i don't know how to script) and then a dialog would say what you and the npc were saying back and forth like "Hey, sorry i'm late." npc: "it's okay, now get in line please. You: Okay." (dialog ends)