How do i add statements to call every method you declared in class?

See more:

C#

namespace Assignment4_2
{
    class SumArray
    {
        public class ProjectArray_Nonyelu
        {
            private int[] data;
            
            public void SumArray(int[] d)
            {
                data = d;
            }

            public int[] SumOfArray()
            {
                Console.Write("Enter an array size: ");
                int size = int.Parse(Console.ReadLine());

                //int i = 0, sum = 0;
                int[] anArray = new int[size];

                for (int i = 0; i < size; i++)
                    //sum += anArray[i];
                {
                    Console.Write("anArray[" + i + "] =  " );
                    anArray[i] = int.Parse(Console.ReadLine());
                }
                return anArray;
            }

            public static int[] SumOfArray(int[] d)
            {
                int[] a = { 5, 4, 6, 8 };

                int x = 0, sum = 0;
                for (int i = 0; i < a.Length; i++)
                    sum += a[i];
                {
                    Console.WriteLine(sum);
                }

                return a;
            }

            public int MaxOfArray()
            {
                int[] c = new int[5];
                int max;

                for (int i = 0; i < 5; i++)
                {
                    c[i] = int.Parse(Console.ReadLine());
                }
                max = c[0];

                for (int i = 0; i < 5; i++)
                {
                    if(c[i] > max)
                    {
                        max = c[i];
                    }
                }
                return max;
            }

            public static int[] MaxOfArray(int[] a)
            {
                int[] b = new int[5];
                int max;

                Console.Write("Enter 5 numbers: ");
                for (int i = 0; i < 5; i++)
                {
                    b[i] = int.Parse(Console.ReadLine());
                }

                max = b[0];

                for (int i = 0; i < 5; i++)
                {
                    if(b[i] > max)
                    {
                        max = b[i];
                    }
                }
                //return b;
                Console.WriteLine("The largest number is {0}", max);
                return b;
            }

            public void DisplayArray(String m)
            {
                Console.Write(m + "{");
                for (int i = 0; i < data.Length; i++)
                {
                    if(i != 0)
                        Console.Write(",");
                    Console.Write(data[i]);
                }
                Console.WriteLine("}");
            }

            public static void DisplayArray()
            {
                int[] a = { 3, 4, 5, 6 };
                Console.Write("{");
                for (int i = 0; i < a.Length; i++)
                {
                    Console.WriteLine(a);
                }
            }

            public static int[] ReadIntArray()
            {
                Console.WriteLine("Enter an array size:");
                int size = int.Parse(Console.ReadLine());

                int[] anArray = new int[size];

                for (int i = 0; i < size; i++)
                {
                    Console.WriteLine("anArray [" + i + "] = ");
                    anArray[i] = int.Parse(Console.ReadLine());
                }

                return anArray;
            }
        }

        public class TestProjectArray_Nonyelu
        {

        }
        static void Main(string[] args)
        {
            /*TestProjectArray_Nonyelu();
            SumOfArray();
            MaxOfArray();
            DisplayArray();
            ReadIntArray();*/
            
        }
    }
}

What I have tried:

I've tried to call all of the methods, but I keep getting errors. I've cancelled it out in the main.

I posted the directions of the assignment, so you can see how I wrote my code. If you can let me know my mistakes I'd really appreciate it.

Create a console application, Assignment4_YourLastName, then add two classes ProjectArray_yourLastName and TestProjectArray_yourLastName to your project.
I. Make your class ProjectArray_yourLastName have:
1. a private variable data of int array type;
2. a constructor which takes one parameter to initialize data;
3. an instance method SumOfArray which returns the sum of data elements;
4. a static method SumOfArray which takes one parameter of int array type and returns the sum of its parameter’s elements;
5. an instance methods MaxOfArray which returns the maximum element of data elements;
6. an static methods MaxOfArray takes one parameter of int array type and returns the maximum element of its parameter’s elements;
7. an instance method DisplayArray of displaying a message and data
8. a static method DisplayArray of displaying a message and an array
9. a static method ReadIntArray of reading an array and returning the array

II. Make your class TestProjectArray_yourLastName only has the Main method. In the Main method, add statements to call every method you declared in class ProjectArray_yourLastName at least once. Note: there are instance methods and static methods. They are declared and used in different ways!!!!!!!