For example:
Tim gets two shifts today which is the one between10:00-14:00 and the other one between19:00-22:00. He was made to punch time clock four times(Clock on twice and clock off twice)
10:00-14:00(The first time employee clock in and out)
19:00-22:00(The second time employee clock in and out)
No matter how many shifts do employees gets, they need to clock in and out in the range of each shift.

Notice:
Do not have two overlapped working time as you are editing employees' shifts.