Out of the subjects you've chose, I only do AQA Maths but taking a look at some of the past papers, Edexcel and AQA are practically the same.
There will most likely be three modules that you study for Maths, those being Core 1, Core 2 and Statistics 1 (or maybe Decision 1),
these are simply different parts of maths that contain certain topics, for example you would probably expect some kind of maths about probability in statistics.
If I remember correctly there is about 8 topics in each module and a quick search on one of the topic names will easily reveal most of the information you need to know for your exam board. (Just google '-insert module here- edexcel topics' )
For example, you may wish to know about Coordinate Geometry from Core 1, or you may want to look into Binomial Expansions from Core 2, or you may want to look into standard deviations in Statistics 1.
You know those people who say 'where will I ever actually use this?' well A level maths will show you where to use it, Differentiation will allow you to find the gradient at a single point on a curved graph where as integration will allow you to find the area underneath a graph, sounds pointless? Well when that graph shows you sales in a business and you want to see how fast it was rising on a particular day, or you want to find out how many sales you had made over the past year, you can use both of the methods described above.
What can I say? I'm a sucker for maths.