Save a new list
To create a custom list use the Contacts filters to the hone in on the contacts you'd like to save as a new list.
Choose the Save New List button to name your new list. Your new list will immediately be added to Custom Lists within the lists drop down.
Update a list
Any changes you make to an existing custom list will activate the Update List button. If you click Update List the list you are changing will be updated and saved with your new filter configuration.