The following workflows are applicable to both the Node Editor and the Hypershade.
When you select an output attribute, some of the input attributes on the right are dimmed, indicating either that they cannot be connected to this type of output node or you must double-click the dimmed attributes to see the nested, connectable nodes.
For more information on the Connection Editor, see Connection Editor.
Middle-drag a node from the Node Editor or the Hypershade work area into a field in the Attribute Editor or Property Editor.
Middle-drag a node onto another in the Node Editor or the Hypershade work area.
Select the attribute you want to connect to from the pop-up menu that appears.