The ATG platform provides client stubs for all ATG platform Web services in ATGWS.dll. Once you have installed a version of ATGWS.dll to your GAC and Assembly folders (see Installing ATGWS.dll for instructions), you need to do two things:
In your Visual Studio .NET project, make a reference to ATGWS.dll.
Create instances of the client stubs and use them in your Web service call.