Included with Kubuntu is the KDE help system otherwise known as KHelpCenter. KHelpCenter not only provides help for Kubuntu but also for the applications and systems that are a part of the K Desktop Environment. To access KHelpCenter go to Application Launcher → Applications → Help. From there, you can search within the system's man pages or within the system documentation created by the man Kubuntu and KDE documenters. The main page is a simple menu layout providing you access to the needed help.