Adding cards (names and addresses) to a list is very easy.
First, select the list by tapping on the list name itself , not the Import button on the right (small box with arrow pointing inwards), which is used when importing cards from another list.
Then simply press the ‘+’ button in the bottom-centre of the next screen. On an iPad, this will be the screen in the right-hand pane.
You will see that you have a choice of how to add names.

Tap the Add Names Manually button to enter names and addresses manually, just for use within AddressLabels. For more information, please refer to Adding Names Manually.
Tap the Import from Contacts button to select names from your devices Contacts.
For more information on adding names from Contacts, please refer to Adding Names From Contacts.
Tap the Import from CSV file button to import names and addresses from a .csv spreadsheet file.
Names added from Contacts are shown in black whilst names typed manually or imported from a csv file are in blue – refer to screen-shot below. “Mary Ann Chivers”, for example, will have been added locally to the AddressLabels Christmas list. She will not appear in the Contacts app on the device.