Download the Zoom installer from http://zoom.us/client/latest/zoomusInstaller.pkg or Check for update in the Zoom app (5th item down in “zoom.us" menu)
If the installer doesn’t start up automatically, find “Zoom.pkg” or “zoomusInstaller.pkg" and double-click it
You should be presented with a dialog box like this Click on “Continue”
You’ll be presented with the 2nd dialog box
Click on “Change Install Location"
You’ll be presented with the 3rd dialog box
Click on “Install for me only” then “Continue"
The install should run to completion and Zoom should be ready for you to use.