Elements on a page are like objects in the real world. They share space and push each other around.
Click and hold an element to start dragging it on a page. If a box has a custom name, it's label will be displayed when an element is dragged over it.
Thick purple lines show where the element will be placed. Elements can be placed above and below, or side-by-side with other elements.
Elements and boxes can also be sorted using the breadcrumbs.