Here are the steps and video on how to install and use Respondus Lockdown Browser on a Apple/MAC Computer:
Click and Go to https://download.respondus.com/lockdown/download.php?id=583239291
Download the LockDown Browser installer package. Depending on the browser setting, it may download as "InstallLDBPackage64c-2-0-x-xx.zip" where "-x-xx" is the current version number.
If the downloaded file did not automatically unzip, locate "InstallLDBPackage64c-2-0-x-xx.zip" (usually in the Downloads folder), and double click on the file to start the Archiver to unzip the file.
Locate the "Install Respondus LockDown Browser xxxxxxxxx.pkg" to start the actual LockDown Browser installer.
Accept all the default prompts to install LockDown Browser.
Go to Finder->Applications and double click on the "LockDown Browser" icon (a world globe with padlock) to start LockDown Browser.
CREDIT FOR VIDEO: Respondus Lockdown Browser