What is the purpose of the Layers, and how can I use them?

Layers are another way of grouping shapes to control their visibility as a group. They work identically to the layers used in typical drafting or drawing software. The visibility of all shapes on a screen follows the visibility of the layer that they belong to. Making a layer invisible, all shapes that belong to that layer become invisible.
Each layer has a number of parameters that can be used to control its visibility. The most important parameters for the layer visibility are the zoom levels. By setting zoom level visibility parameters, you can control at what zoom levels a layer can be visible or invisible.
The result is an ability to clutter and declutter a screen based on the zoom level.
Using animation, you can also set up buttons to control the visibility of a group of objects based on their layers without needing to group the shapes together or set their visibilities one by one.