To
wallpaper a PC.
Right click on the desktop, choose Active Desktop. Under Active
Desktop choose Customize my Desktop. Once in Display Properties
click on the background button and select the file that you
downloaded.
To wallpaper a Mac.
Go to your Control Panels and click Appearance. Once the Appearance
window is open choose the Desktop button. Click the place
picture button, find the image you downloaded and then hit
the Set Desktop button.