请教下Immigration Questionnaire怎么填~~~~~

请教下大家这项是神马意思呀~~~~收到PHD AD后学校要求填Immigration Questionnaire，说是为了发I-20用。这个Questionnaire里面有一项是到达美国的日期，想问下一般要比开学时间提前多久去处理房子等事情啊？多谢大家啦~~原来的题目如下~~
Information About Your Expected Entry to the U.S.:
16.  Date of expected entry in the U.S.: __
NOTE: If you enter the U.S. with a student visa, you must enroll at your intended school at the earliest opportunity. If you do not plan to start classes at Texas A&M immediately upon your arrival in the U.S., please complete the fields below to let us know how to contact you in the U.S. if University officials need to reach you.