offer letter,resume, university script and degree graduate certificate( north ameraica,none NA degree should be valued by UT or some else), if previously worked in canada in the same area take that jobs offer letter and paystub too. AT the airport ,i think is terminal 3 is for US, the INS office will review this and ask some questions normally would be why you go there, for what job, degree, what you previously doing, should answer same as the material you show them. Then if you approved he will ask you to fill a I-94, they he will stamp the date, expire date ( 1yr), multiple entrance