click on the music folder on the pop up thing that came from your ohone and then go to your music folder from your computer and click and drag the songs or artists or folders you want from there onto the music folder on your phone.
if you want to set songs as ringtones, you are going to have to shorten the songs first or else it wont let you because the song is too big so go to http://www.cellsea.com/media/rtindex.htm and then put those the same way from your computer to your phone's files.
hope I helped! if not you can always google it!!! hahah