How to get the music from my iPhone 5 onto iTunes?

I recently bought a new computer with Windows 8 because my last computer crashed. What is the best free way to get the music from my iPhone 5 back onto this new computers iTunes?

You plug it in with your computer. & it'll ask you to sign in & stuff. This process will go faster if you already have an apple account/iTunes. & once you have it registered., it should sync your info( photos, music,& so on) hope this helped

This guide shows how to transfer files from ipod and iphone to computer or itunes:
http://www.ipodtransfer.net/how-to-transfer-songs-from-ipod-to-computer-or-itunes-with-ipod-transfer.html