In order to share your calendar with "user1" there is a two-step process.
 
1.    Log onto the web access to you emails https://exchange.miit.co.nz  and enter your email address and password.
2.    Select calendar from the left hand pane
3.    Select share from the top menu bar and select share this calendar from the dropdown menu
4.    Enter the email address of the person you wish to share with and select the radio button ‘All Information’
 
Next from within outlook 

1.    Select calendar from the left hand pane
2.    Select ‘Calendar Permissions’ from the top command bar
3.    Assign permissions to the users accessing your calandar.