Besides doing this you need to go into the 2nd page of your pack by clicking on the '2' in a circle in the lower right. there are more slots there but they must be unlocked. It is free to do and you can do one every 24 hours. When one is ready to be unlocked that lock in the icon will show as being open. Just click on it and the slot will be available and the next one will start the 24 hour countdown.