I was successfully able to figure out how to use the FTP to upload mods to the server.
1. Stop the server using the Nitrado Interface. (Not the Giants Farming Simulator Interface)
2. Upload files using FTP.
3. Start the server using the Nitrado Interface.
4. Open the Giants Farming Simulator Interface Home Page. At the bottom of the page you must activate the mods.
5. Start server in Giants Interface.
If you upload mods while the server is still running the Giants Interface will not detect the mods at the Home page or Mods Page. If the server is restarted or shutdown using Nitrado manager the mods will be deleted.
Thank you this was most helpful