Full details are supplied in the tutorial at 
http://siempresolutions.co.uk/blog

The short cut is to just copy the files into the App_Code and App_Plugins folders but ensure you change the localhost port reference in the \App_Plugins\UmbExtend\BackOffice\umbExtendTree\umbExtend.umbExtendTree.import.Controller.js

Steve Morgan
Siempre Solutions 
http://siempresolutions.co.uk/
15/05/2014