UI1: Left click on "More" on the bottom menu (between your user name and "Power"), left click on "Advanced Options", on the right hand side of teh screen, 4th button down is "KDE desktop", left click this to start kde
UI2: Left click on the screen to bring up the menu at the bottom, go to "Advanced", at the top will be "KDE desktop", left click that option to start kde
that help?