The procedure to clear back subjects is really simple. You just have to pay a certain challan of Rs. 600 per subject for each SEM you want to retake. Submit an application with the challan receipt and the exam code would appear on your admit card.
Moreover, you don’t have to appear for any kind of internal exams again. You just pay a certain challan for retaking the exam and that’s it.
I would like to advise you that you better study hard and clear the exams in one go. Good Luck.