Save the changes of the layout in the editor with "Save layout" and wait for the confirmation: the changes then apply to the site.
Examples
When I save the layout changes
When we save the layout changes
And I save the layout changes
When I save the changes of the layout
And we save the changes of the layout
Pattern
When(/^(I |we )*save the (?:layout changes|changes of the layout)$/, …)
Part of @webship-js/backdrop-cms-steps (github.com/webship/backdrop-cms-steps), a step pack for Webship-js 2.0.x.