Hello manoranjan,
Let me tell you straight process for becoming RIA
first download the pdf of nism research analyst book
This is available (2015 edition) read thoroughly it’s boring I know.
After that you can take 2-3 month subscription of some online websites like prepcafe (https://www.prepcafe.in), they provide study material with mock test also like simulator environment with MCQ test and same timing as it happens during Exam time (I am not promoting just telling what I did)
After that you can apply for real exam from NISM website by paying fees of 1500/-( crosscheck pls)
The supcription cost of preparation site is approx 500 rs.
I hope it will help
For further query connect at 8586943669