How can I implement binary search into my code?

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C#

I am trying to use binary search to find a user defined number in an already sorted array. I have the binary search algorithm already but I do not know how to take the user input and search for it.

What I have tried:

Binary Search:

static void BinarySearch(int[] arr, int key)
        {
            int minNum = 0;
            int maxNum = arr.Length - 1;

            while (minNum <= maxNum)
            {
                int mid = (minNum + maxNum) / 2;
                if (key == arr[mid])
                {
                    Console.WriteLine(++mid);
                }
                else if (key < arr[mid])
                {
                    minNum = mid - 1;
                }
                else
                {
                    maxNum = mid + 1;
                }
            }
            Console.WriteLine("None");
        }

Space I've tried to call it:

Program p = new Program();
string userInput3;
Console.WriteLine("\nWhich number do you wish to search for in the array?");
userInput3 = Console.ReadLine();
int Int1 = Convert.ToInt32(userInput3);
int Int2 = int.Parse(userInput3);
p.BinarySearch(arr, userInput3);