To start use the script you first need to go to https://developers.google.com/calendar/quickstart/python and press the "ENABLE THE GOOGLE CALENDAR API" to activate it. 
Then you will get a popup with a file called credentials.json, that you will need to download.
After that just add that file to the project root folder and then in the console or terminal you can run it by typing in: python calendarauto.py