Do not change the installation directory from the default that the installer picks. To check whether you are running the latest version, visit the page MIT App Inventor 2 Connection Test, On the Mac You do not need setup software if you are using just the wireless companion.
This is required only if you are using the emulator or the USB cable. If this is your first time setting up App Inventor, go to the main Setup Instructions If you have previously been been using App Inventor on this computer, you may need to update your App Inventor Setup software.