No, there is not a design brief for any of the contest categories. However, the simplest brief for each Rookie of the Year category is to create a single page which shows all your best work that relates to the category (industry) you choose to enter.
For example, if you want to enter Rookie of the Year - Visual Effects, you should create an entry that shows all your best visual effects work. Think of the contest as a job interview. You want to share your best work that relates to the category.