Airbus.De,
Not quite sure what your question is, but I think that your asking for a good method to study.
When I did my PPL exams, I did them one at a time. Study one subject, take the exam. I would recommend this method. You will not be expected to remember everything that is wrote in the Trevor Thom books, but a good understanding is required. Then go to the PPL confuser, and apply the knowledge that you have learnt. Answering questions in The PPL Confuser will teach you what areas you need to know in detail, and which you don't. Also, any weaknesses in your knowledge will be shown when you are trying to answer the questions.
Its one thing learning the material, then you have to learn how to do the exam. This was true in my A Level exams, some topics always came up, and you needed a thourough undersranding, whilst other topics only required a basic understanding.
I've heard that the PPL exams are changing very soon, the old papers cannot be used after March?? I'm sure somebody will correct me on this. Therefore, the PPL confuser questions may not teach you correctly which areas of the a subject need more attention than others.
Hope this helps.