بسم الله الرحمن الرحيم
الاخ الحبيب
اسمح لى ان اكتب بالانجليزية
All you have to do is to read about it before you install it.
Read about filesystem - ext3 - and how it differ from fat32 and ntfs, also mount points and paths.
i think those are the most important things to read before dealing with linux.
Also, you should ask your self a very small question- Why i'm going to Linux, What I do need to do with it? -
As for which distro. you should install I recommend Mandrake - it has a great gui and easy to maintain.
And I think you will find a great help here from our Linux brothers and sisters.
This site you could find many distro., just download any one you want.
http://iso.linuxquestions.org/
and we will be here all the time.