To export your Calendar from your PennO365 account you will want to first log into your PennO365 account through the web interface.  Click on the gear icon in the top right of the page to access your account options.  Select Calendar from the list at the bottom.

Select the Calendar you wish to export and the level of permissions.  You will want to select Full Details so that the exported file can be fully imported into another calendaring system.  Click Save.

After clicking save you will see two links appear.  Click on the bottom link and you will be prompted to download your calendar's .ics file.  This file can then be imported into your personal account.

If you are importing your calendar into a personal Gmail account you can find instructions for doing so here.  Please contact your Local Support Provider if you have any trouble.