How do you see Alolan Dugtrio in Pokemon sun & moon demo?

Question

I heard that we can see Alolan Dugtrio in Pokemon sun & moon demo. So please show me how to see it.

Answer 1

It's a random-encounter NPC you find on the beach. The NPC is not always there, but when you talk to he she lets you open up the Poké Finder and take a picture of Alolan Dugtrio.

Source
Also I know it's a random encounter because of reddit and she isn't there on my demo.