1. How to add friends
Please look at the picture:
Click the 'Invite friends' button: your friendlist will appear and you will be able to add (invite) your friends to play SuperCity.
You can invite only the people who are in your Facebook friendlist.
2. How to delete friends
There are two ways to delete the players who don't play from the friendlist: you can either unfriend them on Facebook or simply ask them to delete the application.