You can see your own or other user's latest 9 friends in the “My friends” widget on your own or other user's profile:

If you're on your own profile, you will in addition see “Edit friends” icon which allows you to search for users to add by looking up the users using the search form and clicking “Add to friends” icon to the right of appropriate user:

Both on your own and other user's profiles you will see link “See all friends” which will show all your friends together:

You can learn other ways to add/remove friends here.