When adding a horizontal layout panel to a page, the page is divided into a series of columns which autofit to the viewport size. Each component added to the horizontal layout is placed to the right of the previous component, and a new column is added to the layout as the component’s container.
Like all other layout panels, the horizontal panel is added to the active component or page by means of a single click.
Adding components to the horizontal layout is as simple as the single click. Simply ensure that you have the horizontal panel layout selected, and click on the components you want to add.
When adding panels as child elements within a layout, always be sure to populate the child elements as well.