How to use Keypad and Joystick library

Hello
I am doing a project and need your help.
I need to do the project using potentiometer. Every time the value read from the potentiometer is 255, it will have to press a key. how do i do this.

Do you know how to use analogRead() to read a value from a potentiometer ?

My question is not that, I want it to press a button every time the value I read is 255

Yes, but unless you can read the value you can't do anything. So, do you know how to use analogRead() to read a value from a potentiometer ?