The app is easy to use. You need to choose a work shift and mark the dates when you work. The application will show the working days in color. Work shifts are available: one work day-one day off, one work day - two days off, one day work - three days off, two days work - two days off, three days work - three days off, four days work - four days off, two days work - four days off, 5WD - 2HD, 3WD - 2HD, 2WD - 1HD, 3WD - 1HD, etc.
For day / night shifts, you need to select the "day / night shifts" checkbox.
You can change the shift yourself. Press and hold on the date and select "Add" or "Delete" in the dialog menu.