I have been trying to connect to Workflow Server: publicserver.knime.org to access the example file but unable to go it. Do I need to do anything different other than using windows ftp and using guest username and pwd.
you cannot connect to the example server via ftp. You need to connect directly from the KNIME Analytics Platform.
Here is how you can do this: https://www.knime.org/example-workflows
You also can parse through the server using the Node Guide, and download single workflows at the end of the pages: https://www.knime.org/nodeguide