Add calibration button

I have i Wheighing scale based arduino code.
Now i have to use serial monitor to calibrate this.
I want to add a calibration button with this code

Calibration sequence should be like as

Calib. Bttn pressed--------(calibrating...EMPTY THE SCALE)------Again bttn pressed(read empty scale)-------(put 2.000 kg load)-----again cali.bttn pressed----(calibration done ,save calib.into EEPROM and show here current load)-----again calib.bttn pressed------get back home screen of my code


If i calibrate again then automatically remove old calibration from EEPROM and store new data