If you are able to view your unavailability, but can't click within the weekly grid to edit the info, your employer has disabled your ability to make any changes.
This probably means they want to approve any changes, making sure they have appropriate coverage for the company's needs.
For assistance in changing your unavailability, please send a message to your supervisor. An admin or manager for your organization will need to add the new unavailability details for you.
If your company does permit employees to enter their unavailability, look here for directions about how to do that.
Need to edit an existing unavailability set instead? Check here for details.
Are you an admin who needs to adjust your settings for unavailability so that employees can enter their own details? Check here for details on how to get to the Settings page that contains that option.
Need to see setting unavailability in action? Check out this video.