How would i go about finishing this code for these array functions to work properly in Visual Studio

Here is what the main looks like

public class ArrayFunctions {

///

/// The persistent file used to load and store data when the Store() and Load() methods are utilized ///

/// internal string PersistentFile { get; set; }

public static readonly string DefaultPersistentFile = "data.txt";

internal Random Randomizer { get; set; }

public ArrayFunctions() : this("data.txt") { }

public ArrayFunctions(string persistentFile) : this(persistentFile, null) { }

public ArrayFunctions(string persistentFile, int? seed) { // TODO: Implement }

public void Store(string[] data) { // TODO: Implement throw new NotImplementedException(); }

public string[] Load(int dataCount) { // TODO: Implement throw new NotImplementedException(); }

public string[] Randomize(string[] data) { // TODO: Implement throw new NotImplementedException(); }

public string[] ShiftRight(string[] data) { // TODO: Implement throw new NotImplementedException(); }

public string[] ShiftLeft(string[] data) { // TODO: Implement throw new NotImplementedException(); }

public string[] Reverse(string[] data) { // TODO: Implement throw new NotImplementedException(); } }