string folderPath = @"C:UsersDavidDesktopFolder";

string firstSubFolderPath = System.IO.Path.Combine(folderPath, "firstSubFolder");
string secondSubFolderPath = System.IO.Path.Combine(folderPath, "secondSubFolder");


System.IO.Directory.CreateDirectory(firstSubFolderPath);
System.IO.Directory.CreateDirectory(secondSubFolderPath);


string subSubFolderPath = System.IO.Path.Combine(firstSubFolderPath, "subSubFolder");
System.IO.Directory.CreateDirectory(subSubFolderPath);
string firstTextFile = "firstTextFile.txt";
string secondTextFile = "secondTextFile.txt";


firstTextFile= System.IO.Path.Combine(subSubFolderPath, firstTextFile);
secondTextFile= System.IO.Path.Combine(secondSubFolderPath, secondTextFile);

using (StreamWriter firstWriter = new StreamWriter(firstTextFile));
using (StreamWriter secondWriter = new StreamWriter(secondTextFile));