Start 3ds Max with an empty scene.

You can load your own models at this time if you would like to export one of your own works.

To export your model to Cesium ion go to File > Export > Export to Cesium ion.

A tutorial for the plugin can be found at https://github.com/CesiumGS/cesium-ion-3ds-max-plugin.

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.