To import events and tasks:
Click the Import/Export icon from the calendar quick actions menu.
The following menu options are shown:
Import
Export
Select Import.
The Import Events and Tasks window appears.
In the Select File section, click Browse.
Select the file you want to import by navigating through the file system.
Select the calendar into which you want to import the events from the Calendar folder selector widget.
Click OK.
When the process is complete, a message box indicating that the import has succeeded appears. If an error occurs while reading the imported file, an appropriate message appears and you will be prompted to try the import operation again.