There must be some kind of club in your school or some way of doing some martial art not MMA in particular. The point of training at a club or gym is that there is equipment which can improve your stamina, strikes, etc... And people which you can spar with which is ultimately the best way to become a good fighter. What you can do is work out alone in your room, there are many home excersises that you can do to become STRONGER but not a better fighter.

Check out Jason Soares.

http://useadime.com/MMAtraining

He's a Professional MMA Fighter (3-0-0) that teaches MMA online.

You really can't.

One, because MMA isn't a style of martial art. And two, because learning on your own is too difficult.

However, you should be able to pick up some moves through detailed videos. You can learn how to jab, throw a straight punch, hook and uppercut pretty easily. That's all you need to defend yourself at school.

Aim for the chin or throat.

Yeah, if they don't offer martial arts classes at your boarding school that will kind of kill it for you. I would focus on trying to stay fit and then go to a gym to train when you graduate or maybe during your vacation time when you are home. You can't learn a martial art from videos and books. Who will correct you when you are doing things wrong?

I would start by going onto youtube and following sixpack shortcuts workouts I mostly use m100's which is a really good all rounder I would also go and buy a pull up bar, punch bag and weights and lastly join a martial arts club try different martial arts stick to the ones you enjoy or if there's a mma club near buy even better! If you don't want to go buying all that equipment then any local gym or martial arts club should have them that you could use for training hope this helps good luck!

if they offer wrestling there do that

btw theses guys are wrong you can learn from videos and books just not nearly aswell as if you learn from a actual instructor who will fix your errors and stuff

join the wrestling team and find a buddy to practice kickboxing with