Hello Kanishka

IIT Bombay one of the premier institution in India is one among the 7 IIT's. The admission process is as follows

1 you have to write JEE main and then get qualified for advanced

2 after qualifying mains you will attend the JEE advanced exam which is considered as the hardest but it's not true if you're good with your concepts and excellent at problem solving then you can crack it. 

3 JEE exam is for all the students who are willing to get in to engineering across the continent. It was previously AIEEE and IIT JEE these both were combined and JEE main and advanced exams came in to picture JEE mains consists of three sections phy chem and maths each for 120 marks and the total getting to 360 (it varies sometimes) you need to qualify your reservation cutoff if there's any or else you need to clear of cutoff if you clear the cut off then you're eligible to write JEE advanced here also the subjects are pcm and the pattern changes frequently. The JEE advanced exam is next level so you'll find it tougher than mains most of the times. Once you clear all the requirements then you'll be called to apply through josaa which deals with admissions and there are nearly 5-6 rounds and one spot round for admission.

Thanking you

Dinesh