Hi there,

Preparation of JEE mains and advanced depends upon the individual's learning ability. Since it depends the clarity of concepts with problem solving so, it is quite difficult to say that whether you can complete the whole lectures of 2 lectures in how many days because you have to understand the concepts along with questions. If you are regular in studies then it will not take more time but just be consistent.

Learning a new concept will surely take sometime to make a grip on that topic. Also, please make a fixed timetable and  stick to it. Kindly make some flash cards which are basically short notes for last minute revision.

I hope this will help you!

Check this link as well: https://engineering.careers360.com/articles/jee-main-preparation-tips

Thank you and good luck der aspirant:)