The Kubuntu team is proud to announce the immediate availability of the Plasma 5 flavor of the Kubuntu ISO. Unlike it's Neon 5 counterpart , this ISO contains packages made from the stock Plasma 5.0 release . The ISO is meant to be a technical preview of what is to come when Kubuntu switches to Plasma 5 by default in a future release of Kubuntu.
When booting the live ISO up, at the login screen, just hit the login button and you'll be logged into a Plasma 5 session.