It’s very easy. In your downloaded package from ThemeForest, you can find the exported file of these pre-made skins. Simply import them in your Theme Options and that’s it! Your new Vertikal powered site will not look like these demo skins.
These are pre-made skins of Vertikal which you can enable them on your site easily. Please note that these sample sites are loading with Ajax which you can simply enable/disable it through your Theme Options page.