Your business closes for a long vacation in the year. So you need to close these dates for all services.
Then go the settings page.
Step 1. Open Holidays tab.
Step 2. To set the Holidays, you need to click on the Holidays field and select the date in the dialog box.
Remind you that this setting is common to all services created, thus, in future, you may cancel any holiday at the level of service, or vice versa, make any day a holiday.