I have no smart phone, so go into the web version from Princess site and put your stuff in there. Would not accept all mine so I was not in green lane.. I just took the paper work like booking confirmation, vaccination certificate from my gov. They asked if my rat was neg, took my photo, gave me the medallion and I was on board in a flash.
I just used the medallion to get on and off ship, open door and buy drinks, just called the waiter over with a wave. Easy.