Antlr4 CodeGenerator Language

Question

I am making a IEC-61131 to C++ converter, which is being done using C#. I have a good Antlr4 grammar file for IEC-61131 and I am using a custom Listener to generate the output C++ code. I know StringTemplate C# could be used to replace my custom Listener. But I cannot find a good example how to use the StringTemplate CodeGenerator and select the CPP Target Language. Can anyone provide direction here? Or provide an example? Here is code I have so far.

            private void Button_Click(object sender, RoutedEventArgs e)
    {
        AntlrInputStream input = new AntlrInputStream(this.ViewModel.stText);
        STLexer lexer = new STLexer(input);
        lexer.RemoveErrorListeners();
        lexer.AddErrorListener(new ThrowExceptionErrorListener());
        CommonTokenStream tokens = new CommonTokenStream(lexer);
        STParser parser = new STParser(tokens);
        IParseTree tree = parser.program();

        if (parser.NumberOfSyntaxErrors > 0)
        {
            Build.Text = DateTime.Now.ToString("yyyy-MM-ddTHH:mm:sszzz") + "\r" + parser.NumberOfSyntaxErrors.ToString() + " Build Error";
            CEditor.Text = "";
        }
        else
        {
            var listener = new ExtractInterfaceListener(parser);
            ParseTreeWalker walker = new ParseTreeWalker();
            walker.Walk(listener, tree);
            CEditor.Text = listener.code;
            Build.Text = DateTime.Now.ToString("yyyy-MM-ddTHH:mm:sszzz") + "\r" + "No Errors";
        }
    }