The Autodesk Inventory Tool installer is provided as a single Microsoft Installer (MSI) file.  You can download the installer from the AIT Installer section.

To initiate the installation process, double click the AIT.msi installer file, this will start the setup wizard.

On the  AIT Setup screen, review the license agreement, and if you accept the agreement, put a checkmark in the I accept the terms in the License Agreement checkbox and click Install:

A link to the Autodesk Terms of Use can be found here:

The installation will commence.  If User Account Control (UAC) is enabled, a dialog will pop up asking Do you want to allow this app to make changes to your device? Verified Publisher: Autodesk, Inc., click Yes to continue.

Once complete, click Finish:

Once complete, click Finish:

The setup process will place a shortcut to the AIT Windows interface on your desktop and within the Start menu: