CAT Preparation

Hi, I am in final year B.Tech from a 4th tier college, placement sessions are going on and there isn't a single company which is giving 6LPA or above in my campus, I am trying referrals too and still I think it's not my cup of tea. I scored 75.4% in 10th, 70.8% in 12th and 64% till now i.e 6th sem in ug.

My college is near IIT Roorkee and last year in congnizance 2024, I have seen the best(IIT Roorkee) and also the worst(my own college), before I used to think we should only work on our skills and colleges stamp is nothing and has no meaning in professional world....but after experiencing a great campus life for 3 days straight in IIT Roorkee...I was very upset on myself for never even trying to prepare for any competition exam after my 12th....I wanna experience that shit again...I started leaning to prepare for CAT but my family told me to 1st prepare for placement...well but my mind is set to crack a tier 1 college now...can some please tell me how to prepare for A,B,C and FMS online, because I don't want my family to spend money on rent in Delhi/noida/gurgaon. I would rather stay at my home and prepare, then live in another city.

My profile is 75.4/70.8/64(till 6th sem) + EWS too, what score do I need for top B school, and how many exams are there?

What could be my best move as of now to get admission in IIM'A