You should set up your Disposable Logins before traveling. It's very fast, but make sure you have a printer available. First, login to your Passpack account and go to Settings > Disposable Logins. Press the Generate button and the screen will change.
(1) Use the plus (+) and minus (-) buttons to choose the number of Disposable Logins that you want to create
(2) Use the plus (+) and minus (-) buttons to choose when they should expire.
(3) Press the Generate button.
When you're done, you will see the list of generated codes, press the Print button (there is no way you will be able to memorize them - they look like a bunch of nonsense). A tiny, anonymous looking window will open. Print it as you normally would.
Store your printout in a safe place together with your travel documents, or clip it and put it in your wallet.
What Does the Expiration Date Mean?
Disposable Logins only work once, regardless of the expiration date. If unused Disposable Logins will be automatically deleted once they expire.