16x2 Lcd screen with UNO, help

Oh those, you need to look for LCD pinout. Most LCD have 14 or 16 pins. In the LCD tutorial link you posted in your first post, you should have scrolled down to circuit, it shows wiring diagram. However I haven't seen one where the 3rd pin is 1 and last pin is 14, almost sound like the pin numbering is reversed.

Standard LCD (normally found on eBay and other sources) has these pinouts:
1 ground
2 Vsource (usually 5v)
3 contrast for LCD (different function if you used VFD)
4 register select
5 read/write (almost always grounded for arduino use)
6 enable
7-10 are D0 to D3 and can be skipped to save pins on arduino.
11 D4
12 D5 all are data pin, it's the instruction LCD gets from host on what to put on display.
13 D6
14 D7 /
15 LED
16 LED These 2 pins can be controlled independently or straight wired to ground and 5v (through current limiting resistor) on LCD pin 1 and 2

I stole this picture long ago:

nearly all character LCD uses this pinout. Those without backlight do no have the last 2 pins. If you have a large LCD with 18 pins (4x40), those has extra control line that'd need to be wired in and they have different pinout.

Since your pinout may be different, I'd google for model (check the PCB silkscreen) and see if you can find datasheet or pinout.