You cannot access until they open the portal. These dates are usually tentative, can open 2 weeks earlier or 5 days later.
The main reason they have these dates is they need to clear out this yr before opening next yr.
What you need to do now is get your recs in order, take the SAT and ACT, practice the PFA, AND if you know you have a medical issue that may require a waiver to get your medical documentation together.
There is a lot of time before the 1st board, the goal is to make the strongest packet, not just being number 1 submitted.