setting count down time via keypad and not code

Hi Guys

Im struggling abit i have a count down timer with disable code.

have it working all great but would like to be able to set the count down timer via the keypad and LCD.

how would i go about doing this?
below is my current code for setting the time

int Scount = 12;
int Mcount = 0;
int Hcount = 0;
int DefuseTimer = 0;