Search for the person via search at the top. When you have located the correct person, right-click their name and click Add to Contacts List. Then, choose a desired contact list.

1) From the Contacts list, search for a person using the seach box.

2) Right-click on the person you wish to add, and click Add to Contacts List. Then, choose a desired list.

TIP: If you find multiple results for the person you searched for, you may view the users Contact Card from the right-click menu to find the right person.

Outcome

The person you have searched for will be added to your contact list.