Hello,
You have to first appear for jee mains examination and then you have to cross cutoff marks of this exam to be eligible to appear for jee advanced.In jee advanced you have to score very high marks as IIT BOMBAY is the top IIT(for cse).So you have to get under 1000 rank in jee advanced so as to get some of the branches.To get CSE branch try to get a rank under 60 as last year cutoff rank for cse was 62 rank.
For full cutoff details visit the below given link:
https://engineering.careers360.com/articles/jee-advanced-cutoff-for-iit-bombay?amp
Good luck.

Hello Pahlavi,

To get admission in IIT bombay you have to write entrance exams like JEE advanced , gate etc. 

You can check the link for entrance exams for iit bombay

Source : http://www.iitb.ac.in/en/entrance-exams

 

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