How to allow install of non app store or identified developers on MacOS Sierra
From: How to Allow Apps from Anywhere in macOS Sierra Gatekeeper


Quit  out of System Preferences

Open the Terminal app from the /Applications/Utilities/ folder and then enter the following command syntax:
sudo spctl --master-disable


Hit return and authenticate with an admin password

Relaunch System Preferences and go to “Security &amp; Privacy” and the “General” tab

You will now see the “Anywhere” option under ‘Allow apps downloaded from:’ Gatekeeper options