What subjects do you do?
Overall, list each topic you do in each of your lessons and base your revision off that. Start with learning the content and then doing exam questions. I done that throughout my GCSEs and also the start of A levels and it is effective. If you do this, I recommend doing 2-3 hours of revision a day, maybe start with 2 until you get used to it. You can always increase to 3 if you need.
Continuing with academics, you can either have a physical calendar or just a digital one to track when assignments/homework is due in to ensure you do it on time.
Now for daily life in general, I recommend waking up in the morning with enough time to have a decent breakfast, have a shower and wake up (approx 1 hour before you leave). After school, i like to do some sort of exercise even if it ends up just being a walk (which helps to improve mental health/well being). Then I usually like to revise in 30 minute chunks with a 5 minute break in between or sometimes longer to include dinner. Then until I go to bed, I relax and do hobbies.
This is my daily schedule if it helps:
7:00-8:00 Breakfast and Shower
8:00-3:15 School (including travel)
3:15-3:30 Snack, relax
3:30-4:20 Exercise (Usually a 25-30 minute beginner workout with often extra breaks that prove I am out of shape)
4:20-4:30 Recover from exercise
4:30-5:00 Subject 1
5:05-5:35 Subject 1
5:40-6:10 Subject 2
6:10-6:50 (Enough time to cook dinner for the entire household and eat)
6:50-7:10 Subject 2
7:15-7:45 Subject 3 (or free time)
7:50-8:20 Subject 3 (or free time)
8:20-10:00/11:00 Free time
I hope this gives you a rough idea of how to manage your time. Also, you can get chat gpt to give you examples too.
Just to add for procrastination, i recommend having something (big or small) to look forward to if you do EVERYTHING you planned to do. And if you don't, you don't get/do the thing