want to change from serial monitor keypad to 4 x 4 matrix keypad

I am making a ph meter and automator need help to implement a 4 x 4 matrix keypad
I am need
any advice would be appreciated

ph_meter_working_8_sep_no-keypad.ino (38.3 KB)

any advice would be appreciated

Start with the examples that come with the library

So the pH meter works with the serial monitor And the keypad works when tested alone can see on serial monitor Need a way to interface the keypad with my existing program

What do you actually want to do with the keypad ?