This image shows the user view with the "Edit Structure /Template" icon selected in Edit mode.
It can be seen that the page is made up of the Heading element, an Inline asset (Image) and this text in a content Editor element.
The floating palette indicates which Template Elements can be dragged and dropped onto this page in order to change the template. The icon meanings are described on the Page Elements page on the left.
(If you don't see the floating palette in this view it means that the Template is locked to prevent further changes to it.)