To automatically warn people if they try to schedule a meeting for a time when you won’t be working, you can turn on working hours.
Working hours are default set to 9 - 5, Mon - Fri, so in order to check on yours and change if necessary simply:
- Open your Calendar
- Click on the Settings symbol in the top right of the screen (shaped like a cog)
- Scroll down to the Working Hours section and set as required
While you're there why not have a look if there are some other settings that might make your life easier too!