Hello Mudit ,

• Pathfinder NDA And NA by Arihant Publications
• Quantitive  Aptitude for competitive examinations by RS Aggarwal
• NCERT books.
• NDA entrance exam by ES Ramasamy.

NCERT books will be helpful from class 6-10th so you can go through those books and learn . You should be aware of current affairs as well.

Hope this was helpful , Thank you.