When creating your website, it is highly recommended to style each page for desktop, tablet, and mobile. Using the display toggle at the top of the screen you can choose which display to edit.
If you have completed the design for a particular display and you want to customize the design for another layout, change to the new layout and click Copy in Desktop/Tablet/Mobile Styles.
You can choose to copy in all section styles or just a single section.
To copy in all styles, go to the sections tab on the left of your canvas and choose which layout you would like to copy.
To copy in just one section, go to the drop down properties box on the top right corner of the section and choose which layout you want to copy.
You can then customise the new layout to be optimised to that particular device.