To turn this setting on please do the following: 

1. Click on Calendars Module 

1. Click Preferences against the calendar you wish to add weekends to and click preferences (top right) 

1. Where it states "Show weekends" ensure this is selected and click save and then return to calendar 

1. This will then add weekends to the calendar. 

1. If you wish to view holiday dates, this can be seen by looking at the appropriate view. If you look at the daily view or monthly view this will then show the holiday days.