So you've had some fun, and now the learning part starts
You're telling you think the breadboard / connections is most likely to be wrong.
An Uno and a 1602 like display isn't a very complicated thing to build.
So maybe best would be to simply tear down your build and start from scratch.
Apart from the backlight, nothing happens at all with your display ?
Do you have a potmeter wired up ?
If so, what happens if you turn that (something should happen).
In case nothing happens, recheck the potmeter's wiring.
If the wiring is good, the display doesn't react to the potmeter and you do not have a multimeter, use the Uno to test the potmeter.
Connect the center pin of the potmeter to an analog input and a LED to an output.
Load a sketch that has the LED vary brightness relative to the input from the potmeter to confirm the potmeter still works.
If you still can't get things going:
- Make a clear photograph of you setup and upload it in this thread.
- Make sure the wires you used are visible and can be visually traced from the photograph.
- Show your code (and don't forget to put that in code tags).
- Tell everything you already tried.Edit: corrected typo's