Default username

open the dashboard klick on users and give youre self a nickname save and look under the field.
there you can find “Display Name publicy as”

now you can use the nickname…

hope thats it?

Or add a new User and set the account to administrator

how to set a account to administrator?

Go to the user tab and select authors & users. there are to radio buttons there where you can either delete (dangerous) or change permission level for the checked users!!