First off your downloading the wrong thing, you need to download the PlanetFactory CE plugin, i've highlighted where the link is on their forums in the image below. http://oi58.tinypic.com/x4necm.jpg After you've done that, open the rar file and extract the "PlanetFactory" folder located inside, into your KSP GameData folder. Once thats done open the same "PlanetFactory" folder you've just placed into GameData and navigated to PlanetFactory\PluginData\PlanetFactory and delete everything inside. Then simply download this mod and drop its GameData folder into your KSP main directory.