I get that part...here is my situation...
So, I have MS Outlook installed on my PC that I sync my iPhone with iTunes. In turn I also then sync MS Outlook to my Google Calendar via Google Calendar Sync...that's the easy part.
Now I also have a new MBP that has MAC Outlook. I am presently syncing my Google calendar with Calendar on my MAC, no problem, but in turn I also want to sync Calendar with my MAC Outlook Calendar so both MS Outlook Calendars on my PC and my MAC are the same....are you confused yet? 😉