Hello aspirant,
Since, you are interested in becoming a scientist, i will guide you to become one.
First you should complete your bachelors degree, which you did.
Secondly do your masters.
You can do msc or some specialised course.
Thirdly and most importantly complete your Phd.
You will be doing reasearch and writing thesis.
Here are some exams you need to clear to do phd:
CSIR-UGC-NET
NCBS
DBT-JRF
TIFR
ICMR-JRF
NIMHANS
JNU entrance exam
GATE

All the best.

To become a scientist you should prepare well for interviews and there is a tough screening process while applying for reputed organisation like isro,drdo

Apply for these organisations

• Bhabha Atomic Research Centre (BARC)
• Indian Space Research Organization (ISRO)
• Indian Council of Agricultural Research (ICAR)
• Indian Institute of Tropical Meteorology (IITM)
• Council of Scientific & Industrial Research (CSIR)
• Aryabhatta Research Institute of Observational Sciences (ARIES)