Where can I find administrator's name and password for my MacBook to make changes?

Hi Hope everyone is keeping safe. I have just become the proud owner of a new MacBook, hurrah. After transferring all my info and settings from my old macbook I now get the following 2 messages.

1. "Restrictions are now in Screen Time".
2. Music wants to make changes enter an administrator's name and password to allow for this.

I enter what I think the answers are but every time but they are not correct. Can anyone offer any suggestions.

As to where I can find the administrators name once I know that I am sure I can get the password.

Thanks

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