Drum Counter Reset

I have reviewed a previous solution you gave regarding reseting the drum counter on my printer. Your procedure was:

Press c interrupt c interrupt within 15sec display goes off enter 24 press start button enter 7 press start button 000 blinks press ca to exit from the program or restart the machine.

I cannot make this work, please help me understand the interrupt? Is that a space of time, a button on the machine, etc. I appreciate any advise on this matter.