Most likely didn't delete your Downloads folder, you simply removed the Downloads folder from your Dock. In Finder (click the smilley-face in the Dock) select Go To->Home Folder in the menu. From your home folder just drag the Downloads folder into the right side of the Dock.
If you cannot find the Downloads folder in your home folder, use Spotlight to find it. Drag it back into the home folder and make a stack of it in the Dock in the way I described above.
If you cannot find your previous Downloads folder using Spotlight, create a new folder in your home folder using the Finder, call it Downloads and create a stack in the Dock.
Top
