Installing Windows 8.1 on Mac

I have a macbook, the brand new ones that just came out and I have just bought and downloaded windows 8.1 to install via bootcamp. Right now the windows file I downloaded is "WindowsSetupBox.exe". But, I keep getting the error message "your bootable usb drive could not be created". I think the .exe file needs to be a .iso file. How do I fix this?

I'm running on the latest OS X Mavericks 10.9.2