Well... First you have to be linked to something like M$ Exchange Server (or to a system using the same protocol).
Without that, the HD/+ Calendar is just dead space that does nothing.
Since I don't have such server, I can't help beyond this point.
I'm using Google calendar as well. You have to sign in using your Google account-the same one you use for Google Play, and it will connect to your calendar automatically. Then just go into calendar settings and change what you need in there.