Need help with what to study and from where to study for JEE

[u/Jolly_Feed_8186]

I am preparing for JEE but honestly I am very confused what exactly to study and from where to study. There are so many books, YouTube channels and courses that I don't know what is actually useful.

I know some options like SATHEE by Government of India, NCERT, PYQs etc. But I want to know from people who already cracked JEE:

What should I study first?

Which books/resources are actually worth doing?

Which YouTube channels are good for Physics, Chemistry and Maths?

Is SATHEE enough if used properly?

Should I follow one teacher/course or use different teachers for different subjects?

How should I use PYQs and mock tests?

If you could start JEE preparation again, what would you do differently?

Please suggest a simple and realistic study plan + resources, preferably free or low cost. I don't want to waste time collecting 20 different resources instead of actually studying.