How to delete songs off your iphone 5?

I've recently purchased an iphone 5, me and brother share an itunes library so firstly i wanted to know how to get previously purchased songs onto the phone, secondly how to delete his songs off the iphone and thirdly, how to stop my iphone rsyncing his songs whenever i plug my iphone back into the computer!

You will go to the music file click on option and you will see delete

Swipe your finger right on the song you wish to delete and a delete button should appear, press it.