Moving parts are SUBOBJECTS....usualy rotating..you jsut place it like you do any other subobject (pay attention where you put the axis) and then in PCS, once you convert it to pof, set that specific object to rotate areound a specific axis...
EXAMPLE:
Let's say we want to make a sattelite dish rotating subobject
in the subobject section of PCS you put this in the properties sub-section:
$special=subsystem
$fov=360
$name=Radar Dish <---- display name
$rotate=3 <---- how long it takes for it to make a full circle
you also set the Movement Type (Rotation Around Axis) and Movement Axis ( Y axis or whatever axis you want it to rotate around)