Are you staying on-site after your off-site first night? In that case, go to the resort early the next a.m. They will have your reservation name at the gate and confirm with your ID. You can check in at 7am, possibly earlier. At check-in, you will get your KTTW card with dining credits and tickets, if you selected those features. Also you will get your car parking pass. You can leave your luggage with bell services. You will probably not get your room number that early. After check-in, get on the resort bus to MK. They should start at least one hour before park opening. Park brochures, current event schedules, etc., are available self-serve at the Concierge desk. Hot breakfast will start at 7am in the food court.
You will get a text/phone message later, indicating what room number you are assigned. When you receive your room number, since you will already have your KTTW cards, you can go directly to your room at any time. Call for your luggage when you get to your room. Disney's got it all figured out for you. Enjoy your stay!