That’s not typically how it works. You need to apply for financial aid before being admitted. Your financial aid package is processed by each school and communicated to you at the time of your admission decision or closely thereafter. If you delay beyond the dates on their website, you financial aid decision could be delayed by weeks or even months. Please pay close attention to the deadlines on each school’s financial aid webpage.
Here is Brown’s:
Did you check the NPC at Brown? What did it say?