Inside the Autodesk App Store, download and run the OneNote add-in. It will show up in your Add-ins tab. 

In order to start taking notes, click on the App, and it will bring up a window. If you are not logged in to your Microsoft account, it will ask you to login. Once you have entered your Microsoft account credentials, the app will ask you for permission to access your OneDrive where these notes will be stored. Once you accept, it will create a OneNote page for your drawing, and you can start typing your notes! As you type these notes, they get automatically saved to the cloud. 

If you open another drawing, it will create another page for that drawing where you can type notes for this drawing. As you switch between drawings, the app will open the page for the current drawing, so that your notes are organized. 

The next time you open a drawing within AutoCAD, the OneNote app will open up the notes you had taken for that drawing!

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) and uninstall as you would any other application from your system.