Hey,

I believe the best source will be YouTube. You should first watch videos of Jadavapur University's Bsc exam analysis on YouTube in order to get a clear idea about the paper pattern, it's syllabus and how much you are prepared for it

There are various YouTube channels who conducts analysis of previous year question papers of different university and trust me they can be the best starting strategy. After that you can search for books in the Store offline.

Hope that helps.

Thank you.