Thanks for the link.
I have seen those instructions before, but they don't apply to my setup.
If I have Chrome running, there's no Profile icon at the top right.
There is only the 3 dots for Settings.
In Settings there is the People section, and Manage Other People, but there's only:
Enable Guest Browsing, and
Show usernames and photos on the sign-in screen
On page you sent the link to, it has a link to:
Add a person to your Chromebook
but this is what I said: starting a new user from scratch on the Chromebook.