You will meet your advisor at your registration program. If you have not yet attended a registration program there is probably limited information that your advisor will be able to give you prior to your advising appointment. If you need to get in touch with your advisor, you will be able to get the advising contact information from your college's website.
The most commonly used ID at U of I is your University Identification Number (UIN). This is a nine digit number that was assigned to you when you filed your application.