Open up Active Directory Users and Computers by going
Start -> Programs -> Administrative Tools -> Active Directory Users and Computers

Either make sure that there is a user that will be used to run Team Calendar (This account will have full mailbox access to everyone's mail account) or create a new one (this is usually a user called "SSWTeamCalendar". This user does not need a mail box).

Create a new user by right-clicking on 'Users' and select New -> User.

Name the user 'SSWTeamCalendar'.

You can use a password of "password" or choose another if you want.

You do not need to create a mailbox for this use.

This step has been completed. Click Back and proceed to Step 2.