The ODCLASS window is invoked with ODCLASS_GUI command.
The window for characteristics viewing, entering and editing is invoked with ODCLASS_PROPERTIES command.

The ODCLASS window contains a hierarchical menu of commands, search by object types and the object type menu window. The object type menu has three tabs: Classification, Recent, Favorites.
To call ODCLASS commands from the menu, press the left mouse button once.
To draw from the object type menu window – double click the left mouse button.
To call ODCLASS commands from the command line – enter the name of the desired command.

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 7/8/8.1/10) and uninstall as you would any other application from your system.