The friend button is when you are friend of someone,the button can be a heart shape in the biography

To make a friend with that new button:

1.-Go to any save of your friend

2.-Click the avatar

3.-Finally click the heart button

4.-Then popups the message "Thanks for making a friend with {user}" and the dismiss button to close the message,it makes all of the friend user saves in fav and the heart button will change to minus button,clicking the minus button will popup the message "Are you sure to remove this friend?" with the yes and no buttons,if you click yes,then will remove that friend an unfav that saves,if you click no,nothing happens