A Flex container is a special zone that is designed to arrange other zones inside it in a special way. Common use cases include:
Centering other zones relative to each other no matter how many there are.
Pulling icons to one side of a card.
Distributing other zones equally inside
To use a flex container:
Create a new flex container by clicking thetable_rowsbutton at the top of the layout editor.
Drag other zones into it using the hierarchy panel on the right.
Select the flex container zone and modify it's properties using the container tab (on the left).