DAZ Studio's content library will never be named "Runtime".  It doesn't need to be named anything specific in fact.  If you don't know where your library is; open Studio, go to Edit/Preferences/Content Library (tab)/Content Directory Manager...(button) and expand DAZ Studio Formats, that is the path to your content library.  If the zip has a "Content" or "My Library" top level folder extract the files and folders inside that top level folder to your content library folder.