They are layers. Like in Photoshop or any other number of programs. For example, while creating a page or master, add a layer for the main nav and within that layer add all parts of the nav. Then you can have all distinct areas separated out.

Thanks I get the idea but I've been trying to figure how to make a layer from compnents? How do I add a layer to a page? etc... I must be missing something.
Yea, this really is not very intuitive or I am more of an idiot than I thought.
I have tried highlighting components then clicking add new layer, dragging components into the new layer.

Ok after painful trial and error it is make a new layer make sure it is the active layer and add components while that layer is active then you can show and hide it.

Whew! that was a lot of work.