SIRI ETC

I HAVE AN IPHONE 4S AND HAVE JUST UPDATED IT. I HAVE BEEN TRYING TO FIND HOW TO USE SIRI BUT TO NO AVAIL. I ALSO HAVE A HUGE PROBLEM WITH MY PHONE GOING DIRECT TO MESSAGE BANK - IS THERE A SETTING I CAN USE TO FIX THIS.

I ALSO HAVE AN ISSUE WITH SELECTING A SONG TO USE AS A RINGTONE FROM MY MUSIC LIBRARY.

HELP!!!!!

ZITA