You can easily enroll yourself in career360 crash course for JEE mains actually there is no need for registration if you are a member of career360 website just login with your credentials on the app or website and click the link below which will directly redirected you to the page of crash course where you can easily download the online classes and watch it later.

There you can also find model test papers which is set according to previous year paper by expert faculty of jee mains that helps you in ranking yourself.analyse the paper write down your weakness and strength work on it you will definitely going to crack the exam.

https://engineering.careers360.com/articles/free-crash-course-for-iit-jee-mains