Hey aspirant, great to see you preparing for JEE Mains. Initially you would need to cover your basics by going through the NCERT books and then solving the back questions and exemplar questions rigorously. You can begin with the most demanding topics in the exam by going through the previous year papers, link for the same has been provided:

https://engineering.careers360.com/download/jee-main-sample-papers-previous-years

After you finish with all those, you can join any All India Test Series to check your preparation level. NTA also provides the NTA Abhyas app where you can check your preparation with a real-time exam experience. You can also visit the detailed review on tips and tricks, books to follow etc. on this link: https://engineering.careers360.com/articles/jee-main-preparation-tips

Hope that helps. All the Best!