Select the contacts you want to link, and then select Clean up. You'll see any contacts that have the same name, email address, or phone number. On the People page, select Manage on the toolbar, and then select Clean up contacts. To link contacts using the Clean up contacts option: On the People page, select two or more contacts, and then select Link contacts in the panel on the right. Linked contacts appear as a single contact. You can link contacts to indicate that they're related, for example if you have several entries for the same person.
