Thank you, Hardon. With your tip that maybe I was probably not even close, I found it!
On this LG Arista running Android 7.0, on the home screen, there is a icon which appears to be a head shot of a person in a circle with the word "Contacts" under it. When I tap that guy, the word 'Phone appears under the status bar in the upper left of the screen, and the tabs Dial, Call logs, Contacts and Groups, with the Contacts tab being selected. So, right away something is weird – it looks like instead of taking me to the Contacts app, it takes me to the Contacts tab of the Phone app. The blog posts I'd been reading told me to click in the menu > Contacts Settings. There is such a menu item, but in this case it's a wrong turn. The correct answer is to click in the menu > Manage Contacts, and in there voila I find Import.
I suppose there are significant differences among phones, and among Android versions.