Careful with this one - can be slippery when wet. I suppose you what to know how to get it on the desktop now. To get your chosen wallpaper to be set as your desktop background can be done in many ways.You can either right click desktop wallpaper beow and then select 'save target as...' (IE & Opera) or 'save link as...' (Firefox). If this is your chosen route, remember where you save it! Now go to wherever it is you normally set your desktop backgrounds for your computer and selected the saved wallpaper.
Another way is when the full screen background has loaded, right click it and choose 'save image as...' or 'set as Desktop Background' or 'Set as Background'. It'll come to you when the time is right. I've never felt so sure of anything. In fact you probably already know. I'll keep a lid on it now.
Return to wallpaper thumbnails.