How do I add a parameter to a method

You can't add parameters to main - it needs to have a specific signature - which means it needs to have very specific input and output parameters, and you adding or removing them changes the method signature and means that the system doesn't "see it" when it looks for the method to call at startup.

You can create a new method, with whatever parameters you like, and call that from your main method:

private static int MyMethod(int x, int y)
   {
   return x * y;
   }
public static void main(string[] args)
   {
   for (int i = 0; i < 10; i++)
      {
      Console.WriteLine(MyMethod((i , i + 1));
      }
   }