For students, here the politics is explained.
For you students who have this great book imposed upon you in a syllabus, here is the best help I can give you with regard to Chapters V and XI, which are in some editions included only as Appendices.
It is interesting to note that at the outset Orwell himself was nonplussed by the alphabet soup of the political situation in Spain. At first he was at a loss when confronted with the idea of right wing communism as you probably are. It was only as he became aware that he was every bit as much in danger of being killed by the “Communists” as he was of being killed by Fascists that he became educated.