Open the cube "Calendar".
Then press the button "Calendars".
You will see a list of all your calendars. A calendar named My calendar has already been automatically created. Click on the calendar you want to share and then press the button "Add members".
Select the people you would like to give access to your calendar and press the button "Ready".
At the bottom you will see the friends who have access to your calendar. Press "Ready" again.
The friends you have invited automatically receive a message that you have shared a calendar with them.
When they read the message, they can press the button "Open" to view it.
They can see that you are the creator of the calendar (Administrator) and with whom you have shared the calendar.
The cube will be added to their home screen automatically if it has not been added yet.