Requirements: OS X 10.11 El Capitan or 10.10 Yosemite or 10.9 Mavericks or 10.8 Mountain Lion or 10.7 Lion or 10.6 Snow Leopard
Instructions:
If you get a "can't be opened because it is from an unidentified developer" Gatekeeper warning: right-click (or Control-click) the application and choose Open, then click the Open button to run the application. (You'll only need to do this once.)