You can still perform the online enrolment, without stating whether you are in receipt of a grant or not.
If you receive the confirmation notice before the start of term (or end of September if you are not on campus), you can then file your grant notice on the enrolment website. This will allow Student Affairs to recalculate the fees.
If this notice arrives after the start of term (or after 30/09 if you are not on campus), you will have to pay at least one-third of the fees. You will be refunded after you file your grant notice on the enrolment website.
Under no circumstances should you declare that you are in receipt of a grant if you have not received any confirmation of it.