I got ER in one subject in my 5th semester and my 6th semester exams are nearby. How do I take admission in PG?

Don't worry about what have you done yet, just focus on 6th semester exams for now. Your reappear in 5th is a big deal, as it costs you another extra semester after degree completion time but it's an opportunity too, as in mean time you can do other profile enhancing courses and programs, you've got