How do I erase old user and become the new user on a iBook G4 I just got from a friend? My friend gave me his iBook G4.

I could not login because I did not know his password.

I have the 2 DVD Mac OS Install disks of the laptop.

After I installed these OS X Install discs, once again I was asked for the old user's password.

How do I do a complete wipe out and then reinstall the OS so I can become the new user?
Dont hit 'continue' after putting in the Install OS disk, instead go to top-left screen where there is a menu with an option to change login password.