Add a Calendar

Good day, if someone can help …

notes in the mail, I click switch to calendar, esquedo the top of the screen, next to the name of the mail user. Below the calendar picker, looking calendars show in the left pane. I click add a calendar and the system gives me a dialog box for me to select the calendars you want. What I wanted was to know what formula or specific command which opens this screen.

Thank you,