Procrastination is a very difficult beast to defeat. It’s about establishing positive routines that become self sustaining. Mind you, I’ve never fully cracked it and sometimes it’s only the pressure of a now too tight deadline that gets things moving.
A few ideas. Schedule study and relaxation times with a reward if you stick to them. Choose somewhere a little inspirational to study that you have to travel to - I went to a library as part of my study routine. Envisage the happy day when the exams are over and you’ve done well thanks to your self disciple. Don’t be too hard on yourself if you have some procrastination lapses, just resolve to get back on track.