With the help of Arduino Stopwatch You can set the time without making any change in the code and it actually let you know when it reaches zero.
Connection is in between Arduino and 16x2 LCD screen.
LCD RS pin to digital pin 12
LCD Enable pin to digital pin 11
LCD D4 pin to digital pin 5
LCD D5 pin to digital pin 4
LCD D6 pin to digital pin 3
LCD D7 pin to digital pin 2
In addition to that wire a 10k pot to +5V and GND, with it's output to LCD screens VO pin (pin3). A 220 ohm resistor is used to power the backlight of the display, usually on pin 15 and 16 of the LCD connector.
After making connections and uploading program into the board. Set the time between range of 1 and 120 minutes. After identifying the time, it waits for 5 seconds and starts counting down. When the time is up, it beeps few times.