Just show them through the basic three buttons, hand it over, watch them get it going and pause it (so you can see that they're using it correctly) and set them loose with advise to ask the roaming front of house chap if they need help. I would say:
40% take to it like they've used it all their lives
20% are over confident so mess it up, but then recover
25% are scared of it, but end up thinking it's amazing
10% ask if they can just borrow the shop's copy of the souvenir guide and give it back later
5% take it, smile, stuff it in a bag or pocket once inside and then complain later "I had no idea what was going on, there's no information in there!"