How do I delete a duplicate child account on Family Sharing?

I accidentally created a duplicate child account under the age of 7 years old. I have been trying to delete this child account for over a year. There are a couple of forums within the Apple Community that are labeled as "solved" but not a single one makes any sense. One in particular says "log in to the child's apple account that you want to delete, then click on data & security and log in under data & security" and I am assuming since the thread was several years ago, that's why it makes no sense whatsoever. PLEASE! Anyone?

[Re-Titled by Moderator]