At some point, your program will let you know when your orientation dates are. Generally, they want you to work on your medical license ASAP as there are timing issues with state medical boards (i.e. it can take a few months and your program/GME office will direct you as to what you need to do for licensing---if you haven't started this already, odds are you will be very shortly); the orientation stuff comes later and they will give you instructions as you get closer to the date. If you're lucky, they will at least give you a date when you first have to report; odds are that your exact schedule is not going to be finalized until late May or June.