Lunches or breaks can be added to shifts when they are first created or at any time. Once you have added this information into a schedule week it will be there when you Import the week into future schedules. This information is added in the shift description field for each shift and then the shift "Helped Hours" can be manually set to account for any lunch or break time.

So for example if you have an 8am to 5pm shift with a 1 hr lunch you can enter those begin and end times and then enter Helped Hours of "8" and then in the shift description you could enter "Lunch at 12."  The shift description can then be displayed on the schedules for both Helpers and Coordinators to see.

You can quickly add this information to multiple shifts using the Multi-Shift Edit schedule view.. 

Note: Using this method WhenToHelp does NOT allow you to graphically see and account for break time coverage within the shifts. If you need to have accurate Helper counts at all times you could in the example above create one shift from 8am-12pm and another shift from 1pm to 5pm. This would allow you to have accurate counts on the Availability/Coverage view.