Sounds like Trevor Thom! In all honesty, you need to cover the whole book. If you haven't already got it, get the PPL Confuser (try any of the aviation suppliers online) - this will give you a good guide.
There really isn't any more to it than this. The APM books do not waste much paper in writing stuff that is not required for PPL and, where it does, it states that it is CPL level.
Cheers
Whirls