A Visualization always requires a Container element to wrap any element or Widget (either one or many) but you cannot wrap a Container within another Container.

On a Container Element, you can define up to 4 Columns and also set different widths for each of these Columns. This gives you the possibility to achieve a wide variety of layouts. These Columns behave differently according to the screen size (such as mobile screens).

This is how our grid system adapts, according to screen's size:

Here you can see an example of the grid system in action and how the columns stack on smaller screens:

Please see the following figure to learn how to add a container, set up the number of columns and customize the width of each column in a Visualization: