A layer is a special container that always fills its parent, usually the page. Use layers to organize a page into stacked planes, such as a background, zones, and widgets, that you can show, hide, lock, or scale separately.
Layers differ from groups in these ways:
The File > New File from Template > Floor Plan and Equipment View templates create pages that are made of layers.
For a detailed reference of properties that affect layers, see Layer Properties.
To create a layer:
Background or Widgets.The order of layers in the Outline determines which layer is drawn on top.