Sorry if this question has been asked before, but i cannot find it anywhere here or on google.

I set up public/private keys, imbedded into my VPS server successfully, it fully works using putty and authenticates and i log in and have full access.

My issue is that i dont want to allow root login, and this SSH key pair was created with root. How do i add the ssh public key to say "newuser" so i can ssh in with "newuser" and not "root" which i want to deny SSH access to?

Thanks