How to switch on and off an HD44780 LCD Display? I have an LCD Display HD44780 model and I was reading his datasheets

I saw the it has the functionality to be switched on/off as stated:


  Display on/off control: D = 0; Display off // C = 0; Cursor off // B = 0;
  Blinking off


and by continue reading it states:



Then he states again:

Display On/Off Control


  D:  The display is on when D is 1 and off when D is 0. When off, the
  display data remains in DDRAM.


But I can't reaaly understand what I fisically need to do, can anyone help me out to better understand?

EDIT:
For better clarify myfinal goal is to completely (power OFF) the LCD screen, I have some NPN transistors and if this would be the best solution, how about the wiring? do I have only to stop suppying VDO?
Assuming that display is initialized in 8-bit mode: to send command such as "Turn display on/off", 


set RS to LOW first (meaning it is command, not data)
set command bits on DB7-DB0 (in your case it could be 0x08 - DB2/DB1/DB0 all LOW to turn off following: display, cursor and blinking)
make a pulse on EN pin LOW-HIGH-LOW (take a 40uS delay before further communication)