In addition, there should be an wpa_supplicant file in the FA32 part which should help you to connect your piratebox to your homenetwork in case of an adapter issue.
You should setup in that wpa_supplicant.conf file your Local network name and password. PirateBox then tries to connect to the local network, if the scripts were not able to find an USB Stick which will work in AP mode.
Then you can find out the IP address of your zero via your access point or home router.