The Adobe Campaign add-on for Dreamweaver is not installed automatically by the Creative Cloud desktop app after you update to Dreamweaver CC 2018.0.
Before you proceed with the resolution, check whether the extension is already installed in your system. To do so, open your Creative Cloud desktop application. In the Home tab, check whether you see the following banner:
If you see the installation message in your Creative Cloud app, Adobe Campaign extension is already installed. Launch Dreamweaver from ACS.
If you do not see the installation message, perform the following steps:
Go to http://adobe.ly/acdw_addon. To download the extension, click the Free button.
If you see an error message in Creative Cloud, sign out of Creative Cloud and sign in again. The sign-in triggers the Creative Cloud app to perform the installation in the background.