How to Start-up your CAT prep

Hello Everyone, I’m a 25 yo Male , OBC , Myquals= Mechanical Engineer, Working in a bank in technology department as Business Analyst(7 Months). I have 2 years of prior experience in mechanical field. I’m appearing for CAT this year. My scores are 100%(10th), 85.83%(12th), 54.37%(Grad). I have a 2 year gap in the education that’s when I worked in the mechanical field.

I’m still in the starting phase of preparation, what material should i follow? Arun Sharma books or should I opt for classes by TIME /IMS/ CATKING etc or should I just prepare by mock tests, I’m a very quick learner. I’m planning to get into top B schools only. Can someone guide me ?