building a multilanguage WordPress website

please i need help ,i am new to WordPress
i want to build a WP website in both arabic and english languages and switch between them .my questions are:
how to achieve that ?? do i build two websites and link them or there is another way ?
my second question is regarding the arabic version : does WP press support arabic ? or do i have to install a WP arabic version ? or there is some other solution ???
any kind of help is greatly APPRECIATED