Hi b1dvbu17,
almost any calendar program allows one to export an ics file. Even windows calendar will let you export.
That said you are better off using a web based one like google calendar so that it minimises the administration load (the plugin will automatically refresh from the web url as often as you tell it too).
And finally, I am finishing off a plugin that will allow one to use either posts (within a category) or custom post types as events to feed into this plugin. It will also generate an ical feed. It will integrate automatically with this plugin (does not need the feed).
I am doing some final testing and will have a demo/test site up soon at https://icalevents.anmari.com/test/ – well it is up, but not configured and the plugin still needs some tweaks!