If you're running the latest version of MacOS Sierra - the following command needs to be added in your terminal server.
sudo spctl --master-disable
More info here - https://www.tekrevue.com/tip/gatekeeper-macos-sierra/
Once the command is run, the "Anywhere" option is available (see below).
Then finFoil needs to be open and the fin file needs to be opened directly from the finFoil program - the file won't open directly from the desktop.