There is no Linux Mint user guide specific to the KDE edition, only for the MATE edition. But then most of what is in that user guide is applicable to all editions of Linux Mint. There was no user guide update for Linux Mint 14. You can use Linux Mint 13'
s. Click that link to download the English version, or find others here: http://www.linuxmint.com/documentation/user-guide/
For KDE, if you open your menu and go to Applications, at the bottom of the list (scroll as needed) you'll find Help. That takes you to the KDE Help Center where lots of documentation is available for KDE applications and settings. Online you can find further documentation for KDE and its applications in the KDE User Base: http://userbase.kde.org/Welcome_to_KDE_UserBase