Just download the 'framework' from their site, follow the instructions.
You will be basically adding their environment -

SET PATH TO "C:\Program Files\Microsoft Visual FoxPro 9 ;
\Tools\eTecnologiaNetExtender\PRGS"
Setenvironment()

then, loading the appropriate .NET DLL's

They have examples in their download, plus you can use your own access to C# methods that you have created in NET, then compiled to DLL.

J