Haresh, the sections covered in exam by Sainik School for class 6 students are: Mathematics, GK (Science and Social studies), Language and Intelligence. You can find the previous year papers on the given link: https://school.careers360.com/articles/sainik-school-question-papers/amp

If you wish, you can also go through the Sainik School Entrance Exam guide for class 6 by Arihant and Upkar publication.