...
In the Schedule Type field, select the option which defines how many working days should be in a week:
- Five days: You can select any two weekdays as days off and mark work hours with or without lunch breaks. By default, the Monday through Friday will be shown as working days. Work hours are shown from 8 a.m. to 4 p.m.
- Six days: You can select any weekday as a day off and mark work hours with or without lunch breaks. By default, the Monday through Saturday will be shown as working days. Work hours are shown from 8 a.m. to 4 p.m.
- Calendar days: You can select any weekdays as days off and mark work hours with or without lunch breaks. By default, the Monday through Friday will be shown as working days. Work hours are shown from 8 a.m. to 6 p.m.
In the Work Days Calendar field, select the calendar which will be used as the base for this work schedule. 
The "Work schedule (create)" form
...
The system calculates the total number of working hours in a week and shows it in the Workweek Duration field.
Click the Save button to save the new schedule or the Save and close button to save the schedule and close the form.
Note. Then, you will need to apply this schedule to the work calendar which is selected as the base. For this, in the Work Schedules list, select this schedule and click Fill by Template in the lower pane. As the result, you will see the year calendar with work days and corresponding work hours distributed according to this schedule's week template. You will need to perform this procedure for each new year.