There is no administrative account in (K)Ubuntu. When you are asked for the
root password you just type in the regular password of the first user
account. You are just an ordinary user until you use this, or use "sudo" in
a terminal window. Passwords from any accounts you set up after the
original account won't work - unless you have repeated the same password
for them of course. Its based on the security model that ordinary users
shouldn't be able to do admin tasks.

Please don't call your self an idiot! By choosing Ubuntu you have proven
yourself a very smart person.