I want to ask about those chapters which are not covered by video lectures , are they not uploaded or have to be studied by using the notes? or if they have been uploaded, can i have the link.
If they are not in the list of lectures, then there are no lectures!
It is because the relevant chapters do not involve calculations and therefore you should read yourself – they are either revision of other papers (such as P3) or are more background reading.
The only exception is mergers and acquisitions. These questions do involve calculations (although the techniques involved are covered in earlier lectures). To help with these questions I have uploaded several lectures working through recent past Question 1’s from the exams. You can find the link to these from the main P4 page.