Navigate to your Google Calendar, and the date(s) you want to create the Out of Office event for.

Select "Create" in the upper lefthand corner of your calendar, and choose "Out of Office" from the drop down menu.

Enter your dates and details, including the option to automatically decline meetings and add a message. Don't forget to save!

You can also set an Out of Office event by clicking on the top portion of the calendar day, above the actual time selection boxes.

Add your event title and click "Out of office"

Click on the date to select a date range or repeating pattern.

Google Calendar

How to set an "Out of Office" event on your Google Calendar, so it's reflected in various apps such as Gmail, Chat, and Contacts. This is different than adding an event on your calendar during working hours; this sets the full day as Out of Office, notifying others of your absence.

Set Out of Office Event on Google Calendar