You need to set LibName1 as the highest priority library, and shuffle the rest down or remove them. The simple way is:
Leave LibDir blank and put the cache name in LibName1. e.g. for a project called "symgen"
Note that the path in LibName1 can also be full filesystem path, or relative to any of the library search paths, but always excludes ".lib" extension. KiCad automatically adds the path of the current project and standard KiCad installation libraries to the library search path. (I use Windows but the same principle applies, use forward slash "/" for Unix or Windows)