The Plugin is provided as a zip file in the Delphix download site. Follow below steps to download plugin:
In the web browser, go to the Delphix download site.
Login to the download site using email and password credentials.
Navigate to the Delphix Product Releases folder.
Go to the Connectors > Continuous Data > PostgreSQL folder and download the Plugin_<version_number>.zip file.
Refer to the section Delphix Engine Plugin Management for further details.