 What isn't something the guest expects the younger man to do?
There is one fact no sane man can quarrel with ... But some men aren't sane; thus it isn't always so! I'm not your father's ghost, even if I do look a bit like him. You will, you know, so why quibble about it? At least, you always have ... or do ... or will. I don't know, verbs get all mixed up. And don't look at the machine out there too long—until you get used to it, you'll find it's hard on the eyes, trying to follow where the vanes go. You're wondering whether to give me a drink, as I remember it. And naturally, since we have the same tastes, you can make the same for me as you're having. It's a real wrench when a man meets himself for the first time. Some kind of telepathy seems to work between two of the same people. So I'll simply go ahead talking for half an hour or so, until you get over it. You know, I could try to change things around by telling what happened to me; but he—I—told me what I was going to do, so I might as well do the same. So let's begin when you get up in half an hour and come out with me. Yes, it'll be pretty obvious it must be a time machine. You've seen it, just a small little cage with two seats, a luggage compartment, and a few buttons on a dash. You'll be puzzling over what I'll tell you, and you'll be getting used to the idea that you are the man who makes atomic power practical. Jerome Boell, just a plain engineer, the man who put atomic power in every home. You won't exactly believe it, but you'll want to go along. You are completely outside of time and space, as best you can guess how things are. Doesn't hurt, and when you pull your arm back, you're still sound and uninjured. Then you feel silly, because you'll remember that I said you'd ask that. Well, I asked it after I was told, then I came back and told it to you, and I still can't help answering when you speak. "Maybe it's no dimension—or it might be the fifth; if you're going to skip over the so-called fourth without traveling along it, you'd need a fifth.
 listen to his directions very carefully
 steal something from a museum  take credit for an invention from the future  run the time machine  listen to his directions very carefully