There is no special procedure that needs to be done in order to sync tunes with another iPhone. Simply connect the iPhone to PC and make sure iTunes detects it. Before that, Windows will automatically install the drivers. Click the iPhone in the iTunes and check the option from the left menu related to PC connection. While the phone is connected, press to download a track and then wait for iTunes to synchronize it. The Sync Tunes needs to be checked in the Music section on iTunes.