Like most programs, SurveyBuilder has using directives, a namespace (more on that later) and a main method.

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;

namespace SurveyBuilder
{
    public class Program
    {
        public static void Main()
        {
            ...

In the C# Beginner Course we will see many of the classes included in these namespaces.