wndclass.style = CS_HREDRAW | CS_VREDRAW; 
  wndclass.lpfnWndProc = MainWndProc; 
  wndclass.cbClsExtra = 0; 
  wndclass.cbWndExtra = 0; 
  wndclass.hInstance = hInstance; 
  wndclass.hIcon = LoadIcon(NULL, IDI_WINLOGO); 
  wndclass.hCursor = LoadCursor(NULL, IDC_ARROW); 
  wndclass.hbrBackground = (HBRUSH)COLOR_WINDOW; 
  wndclass.lpszMenuName = NULL; 
  wndclass.lpszClassName = lpszAppName
 
  to jest moja klasa okna ale ja wiem gdzie to wpisać tylko nie wiem jak??