You can manage the lunch break rules in 'Settings' > 'Calculation Rules' > 'Lunch Break'. There are two basic methods for controlling lunch break:
1. Clock for lunch
Employees need to register a lunch break on a special button when going out for lunch and you just set the maximum duration of the break. They can go to the lunch any time they want.
2. Missing time break
Using this method users clock a regular 'Departure' when going out for lunch. You need to set the start of a lunch period and the duration of it. Your employees should go to lunch within the designated period, otherwise it will be counted as missing time.