It hooks up just like the 15 pin versions.
http://learn.adafruit.com/character-lcd ... cklit-lcdsTop of page says:
After you've wired up the LCD and tested it as above, you can connect the LEDs to the PWM analog out pins of the Arduino to precisely set the color.
So follow the procedure on wiring - pins 1 thru 15.
http://learn.adafruit.com/character-lcd ... racter-lcdThen go to the RGB backlit page for the specifics about pins 16-18.
They are hooked up to the PWM pins on the Arduino.
http://learn.adafruit.com/character-lcd ... cklit-lcdsAs for using the LCD the tutorial is pretty clear - use the built in LiquidCrystal library:
Again reference the RGB backlit page.
That little black caterpillar you just stepped on will set you back a few bucks....