The JNU exam is of 100 marks with 3 hours duration.It is a Computer Based Test  and has multiple choice questions only.1, 2, 3 or 4 Marks are given for a correct response depending on weightage of each question may vary for different programmes and there is no negative marking.You can see the detailed syllabus here- https://university.careers360.com/articles/jnu-syllabus

For preparing for the test try solving a lot of mock test and sample test paper,solve previous year papers as well as they will give you an idea about the paper patter and difficulty of questions, Topics that require more time for preparation must be given more importance. For more detailed preparation tips you can visit - https://university.careers360.com/articles/how-prepare-for-jnu-entrance-exam

For books there is no specific list but you can refer to Jawaharlal Nehru University (Jnu) English Entrance Exam Guide by Rgupta or some e-books in pdf format based on the syllabus topics.