After DDZmScl command is invoked, if you are currently in Model tab (Tilemode is On), you'll be requested to toggle to Paperspace (Tilemode is Off).

After a Pspace Vport is selected, you'll be presented with a dialog box showing the 3 drop down lists from which you can select a zoom scaling factor: Architectural, Engineering and Metric. 

The installer that ran when you downloaded this app/plug-in from Autodesk App Store will start installing the app/plug-in. OR, simply double-click the downloaded installer to install the app/plugin. You may need to restart the Autodesk product to activate the app/plug-in. To uninstall this plug-in, exit the Autodesk product if you are currently running it, simply rerun the installer, and select the "Uninstall" button. OR, click Control Panel > Programs > Programs and Features (Windows 7/8.1/10/11) and uninstall as you would any other application from your system.

The zoom scale factors are designed to work with 1 unit = 1 inch or 1 unit = 1mm drawings.