I presume you have your score in hand and have done basic research to shortlist the five schools. For R1 deadlines, you should have already started on multiple fronts by now: reflections on your career and life to identify meaningful stories, CV, attending webinars/events, networking with adcom, alumni, and students, getting the basic narratives for essays, and connecting with your recommenders.
However, there is nothing to get overwhelmed by. It is a process and a marathon, not a sprint. Your 90-day countdown is already on. Plan well and execute even better.
Keep away from ChatGPT. Do not use it at all for your applications.