Although you can place the Main method in any class, I would recommend creating a class specifically for the purpose of housing the Main method. Here's an example of doing that using our-so far-simple Employee class: -
class Employee { private int employeeId; } class AppClass { static public void Main() { Employee emp = new Employee(); } }
As you can see, the example has two classes. This is a common approach to C# programming even in the simplest applications. The first class (Employee) is a problem domain class, and the second class (AppClass) contains the needed entry point (Main) for the application. In this case, the Main method instantiates the Employee object, and, if this were a real application, it would use the Employee object's members.