A road-map through "Combinatorial Set theory: With gentle intro to independence proofs" I'm going to study independence proofs form Halbeisen's book. It seems that some material is not needed to study independence proofs, so it seems that the book contains more material than my needs.
My goal is independence proofs not combinatorics itself so, I want to get to forcing as fast as I can. 
My question is: Which material do you think  I should cover in a first reading? and which to be skipped or touched briefly? Which chapters in the text is essential ( musts ) to understand forcing and which are not (optional) ?
As an example to clarify my question: Is it necessary to know permutation models, Fraenkel model and know about prime ideal theorem? or this is optional? the same is for chapter $8$ on cardinals and their relations and so on.
 A: Without reading the actual book in detail, it seems to me that you could probably skip chapters 2,6,8-11, and maybe whatever lies after chapter 17. If your current goal is to understand the basics of forcing, and choice related independence proofs.
If you're interested in choice related independence proofs, then learning permutation models with atoms is a very important step. Many proof draw ideas from atom-based construction of models, and it is sometimes easier to wrangle the details in that setting, compared to working with relative constructibility and symmetric extensions.
It is likely that in the list of chapters I wrote, that you can probably skip for your goal, there will be relevant definitions after all. But for this you really need to just read the book, and when the time requires you, flip to the relevant page, and see what's Halbeisen is talking about.
A: I'm not familiar with this book. I recommend "Set Theory: An Introduction to Independence Proofs" by Kunen. Also two books by Jech on forcing (known as the larger and the smaller Jech). An entire chapter in  Kunen on Martin's Axiom precedes the forcing chapters, although Solovay and Tennenbaum needed Iterated Forcing to prove the consistency of Martin's Axiom. You can skip  OD and HOD, and I found his treatment of L (Godel's constructible class) to be cumbersome. I suggest the definition of L in "Lectures In Set Theory",edited by Morley.
