Setup Etherpad on a IIS7 machine with Port 80

I downloaded Etherpad for Windows
On IIS7 Server I’ve created the directory “etherpad” and now I want to access from external. But while IIS Service is working on Port 80 the etherpad service is working on Port 9001.

Can someone explain me please how to create public access?
Is there a configuration of IIS needed and redirecting the data?
Or do I need to change the settings in Etherpad service?