While FSD International as a commercial entity has evolved, the PC-6 Porter has been widely distributed in the freeware community.
Because "The Real FS2004 - FSD - Pilatus PC6 Porter Repack" is a repack, installation is usually a drag-and-drop affair (unlike the original installer which needed registry edits). Here is the standard workflow: The Real FS2004 - FSD - Pilatus PC6 Porter Repack