Studying in Istanbul

Hi, my name is Mai, I joined internations because I thought I could find some help from other members ...
I just finished school in Germany, now I wanna move to Istanbul for studying. But I have no idea where to start planning it - searching informations about universities and residence permission on the internet just doesn't give me many answers. Is there any student from another country in the Istanbul community who could tell me something about how to make it, or somebody else who has an idea?

Do I have to pass a language test before I am able to study in Istanbul?

When do the semesters start? How to get the best way in contact with (for example) Istanbul University?

How to get residence permission??

These questions may sound stupid, but I really need somebody to give me some tips, anything you can tell me is more than just welcome!

Thanks to everyone who's spending time on reading my Thread and answering it :-)