In order to ease the process of page-building and to keep everything organized, pages are divided in 3 layers
The "section" is for vast pieces of pages. Its main purpose is to have a unified background.
The "group" is a container of several elements. Its main purpose is to organize and structure different blocs between them.
The "bloc" is the content itself. A text bloc, a video bloc, a button bloc, etc.
Hovering a layer will highlight underneath layers.
The gear icon open the settings of that particular element.
The two chevrons icon enable you to adjust the position of an element.