On the next page you can see an awesome editor for designing your template. This editor is GrapesJS. You can design your template however you like. For more information click here
You can design your template Responsively. You can design layouts for Desktops, Tablets and Mobile Devices. Select the device icon from the toolbar you want to design.
The above screen will show you how the editor will look like for designing layout for Mobile devices.
Go to GrapesJS editor demo page if you want to familiarise yourself with editor.