Adding Automatic Update Imported From an iCal file

Hello,

I have been using your plugin for a while and it’s great!
I was wondering if somehow I can add this functionality to may plugin without buying the add-on.
Since I am doing a computer science project, I want to get my hands dirty rather than buying everything.
Could you help me how to proceed? The editor section does not seem to contain much codes to be visible, then how can I add some changes?

Best Regards,

https://wordpress.org/plugins/the-events-calendar/