To enable holidays in your account, hover over your profile picture > Locations/Departments/Roles > Locations.
From here, click on the Location you'd like to edit and go to the Holidays tab.
Once you enable holidays, you will see a list of default holidays based on your country setting (see this by hovering over your profile picture > Company Settings > General > Country).
You can then select which holidays you want to enable, and decide whether or not it will impact the scheduled wages.
If you don't want a holiday to impact the scheduled wages, enter '1.0' as the wage multiplier.
To add your own holidays or events, simply click on 'Add custom holiday'.