Step 1: What You Need / Wire it Up
LCD Module (HD44780 compatible)
220 Ohm Resistor (Red-Red-Black-Black) / (Red-Red-Brown) or 470 Ohm or 560 Ohm is fine too
Wire up the LCD module to the Arduino as listed below and illustrated in the Diagrams.
Don't forget to wire in the Pot and the Tilt Switch too as shown.
Wire up the LCD Module as follows:
LCD pin (1) / Vss -> Gnd
LCD pin (2) / Vdd -> 5V
LCD pin (4) / RS -> 12
LCD pin (5) / R/W -> Gnd
LCD pin (6) / E -> 11
LCD pin (11) / D4 -> 5
LCD pin (12) / D5 -> 4
LCD pin (13) / D6 -> 3
LCD pin (14) / D7 -> 2
In addition you need to wire 5V/Gnd to the A/K of the backlight LED (pins 15/16); and wire in a potentiometer to adjust the contrast (pin 3).
Without the contrast adjustment and the backlight the LCD will not Display anything visible.