I ran into an incomprehensible moment in Shield's book C # 4.0, what does this code mean?

Question

Working with date/time

The First Simple Program
Now it's time to move on to an example of a specific C# program. First, let's compile and execute a short program.
/*
This is a simple C# program.
Let's call it Example.cs.
*/
using System;
class Example {
// Any C# program starts with a call to the Main() method.
static void Main() {
Console.WriteLine("A simple C# program.");
}
}
Microsoft's Visual Studio is the main development environment for C# programs. To compile all of the sample programs in this book, including those using the new C# 4.0 features, you will need Visual Studio 2010 or a later version that supports C#.
Create, compile, and run C# programs using . Tell me what does it mean? At this point ?This is a simple C# program.
Let's call it Example.cs.
*/
using System;
class Example {
// Any C# program starts with a call to the Main() method.
static void Main() {
Console.WriteLine("A simple C# program.");
}
}

Answer 1

it prints the string Simple C# program to the console.
what is unclear here