You set the only username and passwords during setup.
In 810, you first install Kubuntu (as you would have done in 1004). Once at the desktop, you click the icon on the desktop to install linuxmce. Once that install process is finished, the terminal will tell you to reboot. Then you set your username in LMCE, and be assigned the temporary 1234 password for certain user specific functions, like watching private media. From then on it will log itself in.
If you are being prompted for a password, it is likely the kubuntu password.