These HowTo's cover several versions of Plasma. Plasma is a constantly evolving product. It is therefore important that you find the HowTo aimed at your version of Plasma. Plasma has the same version number as the KDE Software Compilation that it is a part of. Your distribution should provide this information. You can also find the version number of your KDE SC by opening the Konqueror browser and type "sysinfo:/" in the address line.