Creating stacks in the dock

Drag the Documents folder from the Finder window onto the right side of the Dock.

 

By doing what was suggested above, it will create a dock stack without making any modifications to the original folder or its location at all. That is just the method of putting things in your dock- if you drag a folder to the right side of the dock it will create a stack.

The same is true for adding applications to the left side- drag an item to the dock and release and a new icon (which is essentially an alias) will be created in the dock, leaving the original exactly where you drug it from.