Cupla's work hours are designed for people with regular fixed work hours. The easiest way to use Cupla work hours is as follows:
Tap More
Tap 'Work Hours'
Toggle 'I have fixed work times.'
Tap 'Custom Hours'
Set the 'I work from:' and 'To:'
Tap 'SAVE'
Tap 'Monday - Friday'
Go through and select which days you work and tap 'SAVE'
Tap 'Edit' to change the hours for a particular day and tap 'SAVE'
Tap the 'Back' button
Once you complete this process, open the side-by-side calendar day view and you will see a lightly shaded block covering your side of the calendar on days you work. Unlike regular events, you can book events over this time.
If you are a shift worker with irregular hours, it is more effective to manage your shifts by setting these up as repeating calendar events with Tags.