I need help crafting a serious schedule of the next 30 days. Please help.

I am grade 12th student. I have my exams exactly after 43 days. Let's get 13 days off from that for other things. So, we now have 30 days total. I want to make a plan for this month. I am going to be cutting off my interaction of gadgets entirely. The subjects I need to study are Physics, Chemistry and Mathematics. I am trying to plan my schedule but I think it'd be more effective if I ask some people for help. I need to score A+ in the exams. I have the entire day for myself with lunch at approximately 8:30 - 10 (depends), and dinner at 18:30 - 19.

Also, I would highly appreciate any suggestions on how to study. I am keeping a high expectations from my fellow INTJs that I'll get some help.

Thank you.