What else do you need to know?
Basically everything.
You have some hardware, the LCD display and the Arduino, that are somehow interconnected. I have to know how you intended to connect them (a circuit diagram) and how you actually connected them (a photograph).
You have some software running on the Arduino. This consists of some pre-written (library) code and some that you wrote yourself. I need to see the code along with a description of how it is supposed to function and how each portion of your code works toward that end.
The ultimate output is designed to be displayed on a LCD. I have to know what is supposed to be displayed under some specific circumstances along with what is erroneously displayed.
I'm sure there is more, but that's what comes to mind so far.
Don