I want to transfer songs from WMP to iPhone 5

All my music is in Windows Media Player. I would like to sync it with iTunes so I can put some of it on my iPhone. The only thing I have figured out to do is add a file or folder to iTunes Music Library. When I do it this way none of the info comes in with it like album art, albums ect. My goal is to be able to share my music files between WMP, iTunes and iPhone. I don't want multiple files except as needed for the albums I pick to load onto the phone.