If 00051 - Show Specific Country Holidays is enabled, then the public holidays for the selected country are calculated and inserted automatically.

In the moment only formulas for public holidays of Switzerland are available. 

In setting 00076 - Which Swiss Public Holidays Should Be Shown you can define which public holidays should be recognized as public holidays. Also in 00077 - Insert Bridging Days As Public Holidays you could define if the bridging days should be recognized by default as public holiday.