There's no non-techie way of running Civ IV on 64-bit MacOS anymore, unfortunately. The Mac version is officially dead and unsupported. You have to run the Windows version via compatibility layer software like CrossOver (paid), virtualization like Parallels (paid), or via WINE (free, but extra technical). It's not worth buying CrossOver or Parallels just for Civ4, but if you already have such software I can help you to get Civ4 working on it. Or if you're willing to endure some technical challenge I can help you get it running via WINE. Let me know.