Your first program

All C# code lives inside a class, and the program starts running at the static void Main() method. The line using System; at the top of the file brings in the ready-made tools from System, including Console.

Console.WriteLine prints text and then moves to a new line. To put a value inside a string, write a $ before the opening quote and put the value in curly braces, like this: $"Level {level}". This is called string interpolation.

Every method states the type of value it returns before its name, and the type of each parameter before that parameter's name, so static string Greet(string name) takes a string and returns a string. C# is a compiled language: the compiler checks all of your code before it runs, and if it finds even one type error, the program doesn't run at all and the compiler tells you which line the error is on.