Allow apps downloaded from: Anywhere
To start, you will need to make sure that your security settings allow applications to be installed from anywhere. Go to System Preferences and left-click on 'Security & Privacy':
Left-click on the 'General' tab within 'Security & Privacy' to pull up the app settings:
Unlock the preference pane by left-clicking on the lock located on the lower left-hand corner. You will be prompted to enter a password for your login account. Make sure you use the password to login to your Mac. Once the preference pane is unlocked, select the 'Anywhere' radial button and confirm the selection by click on the 'Allow From Anywhere' button that appears in the window.