How to transfer music to iPhone 3gs from iTunes?

I have the older iPhone 3gs and iTunes. But my itunes does not have the most recent update, it does has the one before it though. I have music on my itunes but I have no clue of how to transfer the songs to the iphone. Any ideas?

Do you have iTunes on your computer?
Assuming you do, can you provide the version of iTunes so I might point you in a direction that will offer you the "how to" sync via iTunes on a computer specifically for the iTunes version you use. I'll actually point you towards the manual for the version.

Generally a iPhone is sync to the computer by plugging iPhone in via a USB port on a computer. ITune on the computer opens up and in the list on the left side of iTunes Devices will show… Here you will see your iPhone. Then you set up what syncs to the phone, and being on the web the first time, sync select sync and your computer will sync the selections you made to the iPhone.