Hello,

I'm having the same problem, and the link you provided is not helpful.  Under "Set up two-step verification", it says:

"1. Go to Sign in to your QuickBooks Online account.
2. In the Two-step verification section, select Turn on."

But it doesn't tell you where to go (i.e., under which menu) to find two-step verification.

A screenshot would be helpful.  This is a consistent problem with QBO.  The advice often tells you how to do something without a screenshot.  I suspect the UI has been changed since a lot of the FAQ was written, and it's outdated.