To add a preference center page separate from the unsubscribe page, make sure the following option "Show the Preference Center when a contact unsubscribes" is turned OFF.
This can be found under Account > Account Settings > Features.
Then in your email, add a link by highlighting the text and choosing the link option in the ribbon and the option of Preference Center should now be listed for you to select.
Now your customers can update any data field or address book that is listed as "public". You can change the access by clicking on Properties in the Contact data fields page for each field or address book and toggling between the Public of Private options.
Your preference center will request the receiver of the email to enter their email (this must match the email address of the original receiver).
Any public fields or address books will be shown to the customer to allow them to update their preferences.