How to concentrate to study for 3/4 hours?

It’s not possible. Instead break it up into smaller intervals with breaks in between. Get a good music playlist and put your phone away until you’re done. If you get tired then stand up and move around a bit. Try to make what you’re studying interesting, try looking up videos or quizlet games or kahoot!s or anything to keep your attention and motivation up. Good luck!

Have motivation like a treat or a tv show. Tell yourself that when you have finished your task you can have your reward.

The first thing is to accept that there is no a magic formula for studying for hours and not having distracting thoughts or feeling of boredom. But there are some methods that you can try. The best way is to try different methods and find the one which works best for you. You can use pomodoro method, studying for 25 minutes and then taking 5 minute break, you can study at the library or you can study by using study musics or forest sounds on fabulous app. The most important thing is not being so hard on yourself at the beginning. increase studying time gradually and avoid burnout. Good luck!