There is no interview for passport stamping. It is simply the step that activates the production of your plastic card while giving you a temporary stamp to show permanent residence status. Depending on where you are stamping, you will wait in line for many minutes or many hours. Then you will be given a ticket number or token. When your number is called, you go to the desk, show the officer you approval notice, passport and last I-94. You will be asked to give a fingerprint and a signature on a form. Sometimes, the officer will ask for all you previous EADs and APs, so it's a good idea to take those with you. A few minutes later, you will get your passport back with an I-551 stamp in it. The you can leave a free person! Your card will arrive anywhere from 3 weeks to 1 year. The officer will confirm the address you want your card sent to.