What is the difference between Add New States and Edit Existing States?

Add New States will allow you to add states to an existing condition. Remember, a state can only be in one condition at a time, so this will only allow you to add states that are not yet attached to a condition. 

Edit Existing States will allow you to choose specific states already in an existing condition to edit. Doing so will move the selected states into their own condition, while copying the settings from the one they were previously within.