How To Set Up User Accounts On First Installing?

I mean I've done it wrong. How to get it right.

I just made a new win10 install on a new hard drive.

And without thinking I gave my username as george - my son's name - and went ahead.

Now he's an admin login. Which is no good.

When I first realised I thought I'd go create another user with admin and reset george down to user.

It is not that simple in win10, is it? I got involved in all sorts of stuff about microsoft passwords and windows passwords and my yahoo account password and god knows what....

What is the simplest way for me to fix this?

Get rid of the george admin account, give me admin and access to his files and make him a simple user?

Option 3 here:
Add User Account in Windows 10 - Windows 10 User Accounts Tutorials

Then make sure to change the new account to administrator:
Change Account Type in Windows 10 - Windows 10 User Accounts Tutorials

Log into your newly created administrator account and then use the same change account type procedure to change george to a standard user account.

Thank you very much. That was very helpful. Job done.

:)