I want to ask whether it is possible to self study p3 with the help of open tution and other online material or it will be quite better if we take a class from good p3 lecture.
It is possible to self-study P3 (and any other paper). However, it is very important do attempt questions and to understand how they are approached. That is where a lecture class can be useful. You might e able to compromise and self-study initially then attend a revision course.