I can't sync music on my computer to my ipod touch; the ipod shows up under Devices in itunes but does not show buttons (Summary etc.) when I click on it. Suggestions?

I can't sync music already on my computer to my ipod touch; the ipod shows up under Devices in itunes but does not show buttons (Summary etc.) when I click on it. I've read through all the Help tutorials but none of them say what to do if the sync options don't pop up when you highlight the device. I've already spent way too much time trying to figure this out and it's driving me crazy! Thanks for any help you can offer.