Just to be sure -- you're talking about Outlook Calendar, and not Windows Calendar, right? They're different programs, I believe. I ask because I noticed your thread title mentioned "Windows Calendar."
If you're using Outlook, which version is it?
The screenshots in that link are for the actual Outlook 2013 or 2016 program (that usually comes with Microsoft Office), not the Outlook.com site. The Calendar app you're referring to is not the same as Outlook, but the app is probably syncing with your Outlook account. Regarding the events that you want to export, do you know if they're associated with your Outlook account or some other account?
Office Home & Student 2013 doesn't include the Outlook program: https://www.amazon.com/Microsoft-Of...ag=hawk-future-20&ascsubtag=UUacUvbUpU5577544
This looks like the best way to export your Outlook.com calendar into an ICS file, which can then be imported into Google Calendar: How do I export my new Outlook.com calendar - Microsoft Community