I don't know for sure what setup you have, but after reading your post, I went to my time; clicked on it, and up came my calendar. I just [yesterday] upgraded from Win7 to Win10 Home as you did, and am here to try to understand a few things, as apparently, you too have done.
Other than acknowledging that my calendar is there, I don't know what to say.
I recently upgraded to Windows 10 from Windows 7 (free upgrade) and discovered that when I click on the time in the right corner of the taskbar, the calendar does not appear as it used to in Windows 7. I have found information on how to turn on and off the clock icon on the taskbar but nothing that indicates why there is no calendar appearing at all.
Does this have something to do with being upgraded from Windows 7 or with being a free upgrade?