There is a special rule for short breaks in the 'Calculation rules' tab.
Choose the option 'Accept short breaks as paid time' if you want these breaks to be counted in the paid time.
Choose the option 'Ignore missing time during short breaks' if you don't want them to be counted in the paid time.
If you choose to 'Disable' short breaks, All Hours will warn you about the violation of required time rule every time someone takes a break.
You can also set the limits for the number of breaks and their duration.