Configuring the Mapfile
From ARK
Initial Setup
You need to ensure that Mapserver is setup to server as a WMS/WFS server. If you are not sure, please visit WMS Server HowTo and WFS Server HowTo.
The mapfiles themselves need to be setup manually per Mapserver setup - ARK will not write these for you unfortunately, so its worth undertaking the mapfile setup alongside the official mapfile documentation.