Use the Calendar API to create an Event via Google Apps Script. Includes a tutorial video.
This is a simple Google Apps Script file that may look lengthy but in actual fact is just each possible item of an event that a user may wish to modify. Some of the items have default values which means you could remove them from the script and the Calendar API would use these defaults instead. My hope is that laying out the format like this allows you to then manipulate as you require and learn as I did.
Source: The Gift of Script: Create a Google Calendar Event via the Calendar API
I use Google Apps Script to support staff and students in my job. I enjoy dabbling with creating tools to help with automation and I freely share my learning experiences on my blog, where I also have a number of useful Google Add-ons: www.pbainbridge.co.uk