I was in the same situation when I started my preparation. I strongly suggest you to go to academy, I went UQAIPS for guidance its in Clifton. Well it is obvious that you have to work on your own but as you said you're a beginner and know nothing about CSS so, in that case go academy talk to teachers they will guide you and second thing you'll make friends there as well, keep in touch with them make a group, share your opinions and take suggestions. After few weeks you will have a clear picture of what do have to do ? From CSS forum, fpsc website and other internet links you won't be able to collect all the information you need because right now there are a lot of questions in your mind and you won't be satisfied unless you have answers of all of them. There is program going to start in Karachi university on 16th of may take admission there I have been there and they have really good teachers for CSS subjects. Once you're on your way to exam discuss your opinions and start new threads here on CSS forum, it will boost your prep
Good luck mate (Y)