Answer:
Hey sis, I hope you are doing well and I recently got a piece of news that you have got a chance at Jadavpur University and I am happy to hear that. The only thing that strikes me is that you will be living in hostel and life in a hostel is different, I just want to share some do's and don'ts with you and those are you should be humble to your seniors and should be punctual.
And the don'ts are you should not be annoying to others, try to stick with your own words and don't do if someone forces you to do something.
That's all, Hopeyou will have fun in the hostel.
Yours lovingly,
(Your name)