book store form saudi arabia would to publish the books through ibooks store what is the roles

Have a look at these two pages (there isn't currently an iBookstore in Saudi Arabia so you won't be able to sell them in your own country, only those listed on the second link) :

Selling in the iBookstore : http://www.apple.com/itunes/working-itunes/sell-content/books/

Authors and Publishers FAQ : http://www.apple.com/itunes/working-itunes/sell-content/books/book-faq.html

Note that Arabic language books are not yet accepted by Apple's iBookstore.