1st, thank you for your responces Warboy and y-something or other.
2nd, I know I'm doing something wrong. I've extracted the file several times, and I now have sub folders named openxcom in both the main openxcom folder and the data subfolder. I'm guessing I need to somehow copy the info to the various folders, but I'm not 100% certain how to proceed. So I'm feeling rather cautious. Please advise.
3rd, What the hell is a milestone in software speak? I know what physical one is. I looked up what a software is (something about a pre alpha version), but it didn't make sense given the context:
1) unzip in a totally new directory
2) move the directories GEODATA, GEOGRAPH, MAPS, ROUTES, SOUND, TERRAIN, UFOGRAPH, UFOINTRO from "data" of the milestone install to the "data" of the above directory
3) uninstall milestone
Are you telling me to move the data from the orginal folder to the recently made folder?