You should score around 265 marks in JEE Main to get CSE branch in IIIT Hyderabad general category.

You should also fulfil minimum eligibility criteria that is you must have 75% marks in your boards exam or you should be in top 20 percentile in general category.

To score good marks in JEE Main make sure your concepts are clear you can take help of NCERT books to make your fundamentals strong. Refer previous year papers to understand the exam pattern and level of questions. Practice as much as you can. Solve unlimited MCQs. You should also solve complete mock test series to work on time management and to judge your preparation level.

Good Luck!!