Hello.

You should visit this link:

https://jeemain.nic.in/jeemainapp/loginoption.htm

You need to login with your application number. You will be provided with all the correct answers provided by NTA,  you can change the options in paper 1 and 2 and select 'Save your Claims'. You should also upload supporting documents and pay a fee in order to challenge the answer key. The fee is Rs. 1000 per question that you challenge.

Hope this helps.