Especially when there’s a book already …
I think many people coming from “feature phones” have problems at first because a smartphone simply is much more a real computer with an OS and all related quirks than those feature phones pretended to be.
Long-tapping a thing is an example of this, because it simply is the equivalent of the right-click in most desktop OSes, it’s bringing up the context menu translated to touch input.
It always helps not being alone with a certain device, having someone around who can simply show you stuff because he/she has the same or a similar device and knows stuff already … but if all else fails, we’re here for you .