Im on my phone so i cant see what this link is but try it?
Quote from the link you sent
Let us start by importing the custom node. From Dynamo for Civil 3D, select ‘Import Library…’ from the ‘File’ pull-down menu and select Excitech.dll. You should now see an ‘Excitech’ branch in the Add-ons section of the left panel that contains the AddStations node. Click on it to insert it in the graph.