so I'm trying to use an LCD screen and its only showing 16 black bars its a 16 x 2 topway LCD screen btw is there a way to wire it up without a potentalmeter?
hellow! Im new to this website so please be kind! :D
Welcome! 
If you'd like people to help you, please post:
- a schematic (or at least a photo of the wiring),
- your sketch,
- and the exact LCD module you're using.
That will make it much easier to identify the problem.
At this point we have lots of displays to chose from and they are not the same. Without your annotated schematic and code as requested by @InquisitiveMind we have no way of knowing what you have and with that information we can only guess. Answering this is about the same: If I said its blue what am I talking about?
the LCD screen is a Topway (P050001501) LMB162ABC LCD screen
I'm afraid those pictures are of no use whatsoever. They need to be in focus, well lit, and clearly show where wires start and end. Think about it for a moment; if you were trying to help me and I showed you those dark, fuzzy images, could you tell anything from them?
Try connecting pin 3 directly to GND. It's not ideal, but frequently provides a usable display.
If that gives too much contrast then try various resistors (start with 1000 ohms) between pin 3 and GND.
Don
Just out of curiosity: is there a reason you chose the parallel interface instead of an I²C version? It would free up quite a few GPIO pins.
The data sheet for your display shows a 5K rheostat between pins 1 and 3. As @floresta has told you in post # 8, you can try just grounding pin 3 or you can try a fixed resistor up to 5K. Try that and report back.
To deal with your first problem I'll refer you to a proven procedure that, as far as I can determine, I last posted almost 9 years ago. Check this out --> https://forum.arduino.cc/t/16x2-backlight-works-but-characters-dont-display/466601/9
Don