Primary calendar is your personal calendar. But in addition you may have additional calendars for specific teams. Usually there is also a Company Calendar and / or Training Calendar. How do we keep track of multiple calendars? Because time is common. No problem. It is a ONE CLICK solution!
Open the calendars. They will open side by side. It is confusing. But don’t worry.
click on the left pointing gray arrow next to the calendar name. That is called Overlay mode. Now both (or multiple) calendars overlap each other nicely. Unique color is assigned to each calendar automatically. So color tells you which kind of appointment it is.
Click on the heading of required calendar to add appointments to it. That color automatically becomes prominent.
Outlook is smart enough to save personal appointments to your mailbox and shared items to SharePoint (or whatever the source is). That’s It. Use it and share the knowledge.
This is possible for last 10 years. What were we doing? 
If you add too many calendars, the view becomes confusing. That is when you go to SCHEDULE VIEW. I won’t tell you how it works. You figure it out – Homework for you!
