To open calendar and address book in window 10

For Calendar

 >Press window button

>Type calendar and click on calendar app to use calendar.

For Address Book

>Press window button

>Type People and use People App

> In window 10 Address Book name has been changed to People.

or if it is not showing in search button (window click) right click on taskbar and click on show people on the taskbar

or Go to Control panel and click on (Taskbar and navigation) and click on on button of (Taskbar and navigation)