Generally speaking the opening is the earliest an employee can start and the closing is the latest and employee can finish.
To modify the hours of your organisation you must:
- Go in the "Settings" menu
- "Employee Scheduling" tab
- It is then possible to change the opening (pink box) and the closing (blue box)
PS: Only admins can make this change but you can override it. Simply type with your keyboard the time instead of selecting it in the dropdown menu.