In Blender;

1. click File -> Append
2. browse to your downloaded .blend file
3. open the Materials folder
4. import the Node Library material.

All the UV Grid nodes will now be available from the Add Node menu in the Shader Editor.

To learn the nodes, what they do, and how to use them, there is no better resource than the UV Grid Tutorial Series itself!

This series is ongoing and further videos will be posted with new nodes and new materials!