By clicking Work break and then Custom settings you get to the page where you can set your daily work break:
In the first drop-down menu you decide if you generally want to automatically schedule a daily work break (Schedule). With Begin and End you can set the time frame for the work break, i.e. earliest start and latest end. With the drop-down menu Duration you define the duration in minutes. The time frame has to be at least as long as the duration. A longer time frame provides portatour® with some leeway for optimized scheduling, which is especially needed when customer business hours are limited or customer calls generally require more time. If the work break should be scheduled exactly despite offering less optimization, set the duration to the length of the time frame.
The time settings will be ignored if you select Don't schedule in the first drop-down menu.
Press Save to apply the new setting. Organization default resets the work break settings to the default values of your organization.