Reading buttons on a TM1638 LED & KEY module

My first question here so please be gentle.
Without the use of a library can someone give me a few hints and tips how to read the buttons on these module to do something on the main arduino instead of simply illuminating the LEDs on the TM1638 module.
I understand I need to set the thing into “Read key scanning data” mode with a 0x42 command but after that I’m flummoxed.


The data sheet for the IC is at

As implied previously I've got 80%+ of what I'm trying to get working but just need a little input from someone else who may have used the LED & KEY device previously.
All the demos I've found on-line seem to use the buttons to only light the on-board LEDs.



Thank you so much for all your kind and considerate assistance.
I must be missing something. As I see it is The fundamental problem in my mind is; if the arduino sends 0x42 it putting the LED & KEY module into Read Key Scanning Data mode and the data line becomes an input to the arduino.
If as I suspect the LED & KEY module resets the data line to an input after outputting the key status to the arduino how does the arduino grab that data?